关于Sql Server数据库连接池的使用
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最近在使用Java的数据库连接池，那么C#针对Sql Server有没有数据库连接池呢？
首先我们需要一个数据库连接字符串，例如："Data Source=server;Initial Catalog=test;User ID=sa;Password=123456;"
其实这个连接字符串的配置对应着一个类：System.Data.SqlClient.SqlConnectionStringBuilder，在这个类中详细的规定了联机的具体参数，
下面看看这个类的具体代码：
[TypeConverter(typeof(SqlConnectionStringBuilderConverter)), DefaultProperty("DataSource")] public sealed class SqlConnectionStringBuilder : DbConnectionStringBuilder { // Fields private ApplicationIntent _applicationIntent; private string _applicationName; private bool _asynchronousProcessing; private string _attachDBFilename; private bool _connectionReset; private int _connectTimeout; private bool _contextConnection; private string _currentLanguage; private string _dataSource; private bool _encrypt; private bool _enlist; private string _failoverPartner; private string _initialCatalog; private bool _integratedSecurity; private static readonly Dictionary<string, Keywords> _keywords; private int _loadBalanceTimeout; private int _maxPoolSize; private int _minPoolSize; private bool _multipleActiveResultSets; private bool _multiSubnetFailover; private string _networkLibrary; private int _packetSize; private string _password; private bool _persistSecurityInfo; private bool _pooling; private bool _replication; private string _transactionBinding; private bool _trustServerCertificate; private string _typeSystemVersion; private string _userID; private bool _userInstance; private static readonly string[] _validKeywords; private string _workstationID; internal const int KeywordsCount = 0x1f; // Methods static SqlConnectionStringBuilder() { string[] strArray = new string[0x1f]; strArray[0x1d] = "ApplicationIntent"; strArray[0x17] = "Application Name"; strArray[12] = "Asynchronous Processing"; strArray[2] = "AttachDbFilename"; strArray[13] = "Connection Reset"; strArray[0x1b] = "Context Connection"; strArray[0x10] = "Connect Timeout"; strArray[0x18] = "Current Language"; strArray[0] = "Data Source"; strArray[0x11] = "Encrypt"; strArray[8] = "Enlist"; strArray[1] = "Failover Partner"; strArray[3] = "Initial Catalog"; strArray[4] = "Integrated Security"; strArray[0x13] = "Load Balance Timeout"; strArray[11] = "Max Pool Size"; strArray[10] = "Min Pool Size"; strArray[14] = "MultipleActiveResultSets"; strArray[30] = "MultiSubnetFailover"; strArray[20] = "Network Library"; strArray[0x15] = "Packet Size"; strArray[7] = "Password"; strArray[5] = "Persist Security Info"; strArray[9] = "Pooling"; strArray[15] = "Replication"; strArray[0x1c] = "Transaction Binding"; strArray[0x12] = "TrustServerCertificate"; strArray[0x16] = "Type System Version"; strArray[6] = "User ID"; strArray[0x1a] = "User Instance"; strArray[0x19] = "Workstation ID"; _validKeywords = strArray; Dictionary<string, Keywords> dictionary = new Dictionary<string, Keywords>(0x34, StringComparer.OrdinalIgnoreCase); dictionary.Add("ApplicationIntent", Keywords.ApplicationIntent); dictionary.Add("Application Name", Keywords.ApplicationName); dictionary.Add("Asynchronous Processing", Keywords.AsynchronousProcessing); dictionary.Add("AttachDbFilename", Keywords.AttachDBFilename); dictionary.Add("Connect Timeout", Keywords.ConnectTimeout); dictionary.Add("Connection Reset", Keywords.ConnectionReset); dictionary.Add("Context Connection", Keywords.ContextConnection); dictionary.Add("Current Language", Keywords.CurrentLanguage); dictionary.Add("Data Source", Keywords.DataSource); dictionary.Add("Encrypt", Keywords.Encrypt); dictionary.Add("Enlist", Keywords.Enlist); dictionary.Add("Failover Partner", Keywords.FailoverPartner); dictionary.Add("Initial Catalog", Keywords.InitialCatalog); dictionary.Add("Integrated Security", Keywords.IntegratedSecurity); dictionary.Add("Load Balance Timeout", Keywords.LoadBalanceTimeout); dictionary.Add("MultipleActiveResultSets", Keywords.MultipleActiveResultSets); dictionary.Add("Max Pool Size", Keywords.MaxPoolSize); dictionary.Add("Min Pool Size", Keywords.MinPoolSize); dictionary.Add("MultiSubnetFailover", Keywords.MultiSubnetFailover); dictionary.Add("Network Library", Keywords.NetworkLibrary); dictionary.Add("Packet Size", Keywords.PacketSize); dictionary.Add("Password", Keywords.Password); dictionary.Add("Persist Security Info", Keywords.PersistSecurityInfo); dictionary.Add("Pooling", Keywords.Pooling); dictionary.Add("Replication", Keywords.Replication); dictionary.Add("Transaction Binding", Keywords.TransactionBinding); dictionary.Add("TrustServerCertificate", Keywords.TrustServerCertificate); dictionary.Add("Type System Version", Keywords.TypeSystemVersion); dictionary.Add("User ID", Keywords.UserID); dictionary.Add("User Instance", Keywords.UserInstance); dictionary.Add("Workstation ID", Keywords.WorkstationID); dictionary.Add("app", Keywords.ApplicationName); dictionary.Add("async", Keywords.AsynchronousProcessing); dictionary.Add("extended properties", Keywords.AttachDBFilename); dictionary.Add("initial file name", Keywords.AttachDBFilename); dictionary.Add("connection timeout", Keywords.ConnectTimeout); dictionary.Add("timeout", Keywords.ConnectTimeout); dictionary.Add("language", Keywords.CurrentLanguage); dictionary.Add("addr", Keywords.DataSource); dictionary.Add("address", Keywords.DataSource); dictionary.Add("network address", Keywords.DataSource); dictionary.Add("server", Keywords.DataSource); dictionary.Add("database", Keywords.InitialCatalog); dictionary.Add("trusted_connection", Keywords.IntegratedSecurity); dictionary.Add("connection lifetime", Keywords.LoadBalanceTimeout); dictionary.Add("net", Keywords.NetworkLibrary); dictionary.Add("network", Keywords.NetworkLibrary); dictionary.Add("pwd", Keywords.Password); dictionary.Add("persistsecurityinfo", Keywords.PersistSecurityInfo); dictionary.Add("uid", Keywords.UserID); dictionary.Add("user", Keywords.UserID); dictionary.Add("wsid", Keywords.WorkstationID); _keywords = dictionary; } public SqlConnectionStringBuilder() : this(null) { } public SqlConnectionStringBuilder(string connectionString) { this._applicationName = ".Net SqlClient Data Provider"; this._attachDBFilename = ""; this._currentLanguage = ""; this._dataSource = ""; this._failoverPartner = ""; this._initialCatalog = ""; this._networkLibrary = ""; this._password = ""; this._transactionBinding = "Implicit Unbind"; this._typeSystemVersion = "Latest"; this._userID = ""; this._workstationID = ""; this._connectTimeout = 15; this._maxPoolSize = 100; this._packetSize = 0x1f40; this._connectionReset = true; this._enlist = true; this._pooling = true; if (!ADP.IsEmpty(connectionString)) { base.ConnectionString = connectionString; } } public override void Clear() { base.Clear(); for (int i = 0; i < _validKeywords.Length; i++) { this.Reset((Keywords)i); } } public override bool ContainsKey(string keyword) { ADP.CheckArgumentNull(keyword, "keyword"); return _keywords.ContainsKey(keyword); } private static ApplicationIntent ConvertToApplicationIntent(string keyword, object value) { return DbConnectionStringBuilderUtil.ConvertToApplicationIntent(keyword, value); } private static bool ConvertToBoolean(object value) { return DbConnectionStringBuilderUtil.ConvertToBoolean(value); } private static int ConvertToInt32(object value) { return DbConnectionStringBuilderUtil.ConvertToInt32(value); } private static bool ConvertToIntegratedSecurity(object value) { return DbConnectionStringBuilderUtil.ConvertToIntegratedSecurity(value); } private static string ConvertToString(object value) { return DbConnectionStringBuilderUtil.ConvertToString(value); } private object GetAt(Keywords index) { switch (index) { case Keywords.DataSource: return this.DataSource; case Keywords.FailoverPartner: return this.FailoverPartner; case Keywords.AttachDBFilename: return this.AttachDBFilename; case Keywords.InitialCatalog: return this.InitialCatalog; case Keywords.IntegratedSecurity: return this.IntegratedSecurity; case Keywords.PersistSecurityInfo: return this.PersistSecurityInfo; case Keywords.UserID: return this.UserID; case Keywords.Password: return this.Password; case Keywords.Enlist: return this.Enlist; case Keywords.Pooling: return this.Pooling; case Keywords.MinPoolSize: return this.MinPoolSize; case Keywords.MaxPoolSize: return this.MaxPoolSize; case Keywords.AsynchronousProcessing: return this.AsynchronousProcessing; case Keywords.ConnectionReset: return this.ConnectionReset; case Keywords.MultipleActiveResultSets: return this.MultipleActiveResultSets; case Keywords.Replication: return this.Replication; case Keywords.ConnectTimeout: return this.ConnectTimeout; case Keywords.Encrypt: return this.Encrypt; case Keywords.TrustServerCertificate: return this.TrustServerCertificate; case Keywords.LoadBalanceTimeout: return this.LoadBalanceTimeout; case Keywords.NetworkLibrary: return this.NetworkLibrary; case Keywords.PacketSize: return this.PacketSize; case Keywords.TypeSystemVersion: return this.TypeSystemVersion; case Keywords.ApplicationName: return this.ApplicationName; case Keywords.CurrentLanguage: return this.CurrentLanguage; case Keywords.WorkstationID: return this.WorkstationID; case Keywords.UserInstance: return this.UserInstance; case Keywords.ContextConnection: return this.ContextConnection; case Keywords.TransactionBinding: return this.TransactionBinding; case Keywords.ApplicationIntent: return this.ApplicationIntent; case Keywords.MultiSubnetFailover: return this.MultiSubnetFailover; } throw ADP.KeywordNotSupported(_validKeywords[(int)index]); } private Keywords GetIndex(string keyword) { Keywords keywords; ADP.CheckArgumentNull(keyword, "keyword"); if (!_keywords.TryGetValue(keyword, out keywords)) { throw ADP.KeywordNotSupported(keyword); } return keywords; } protected override void GetProperties(Hashtable propertyDescriptors) { foreach (PropertyDescriptor descriptor in TypeDescriptor.GetProperties(this, true)) { bool flag2 = false; bool isReadOnly = false; string displayName = descriptor.DisplayName; if ("Integrated Security" == displayName) { flag2 = true; isReadOnly = descriptor.IsReadOnly; } else { if (!("Password" == displayName) && !("User ID" == displayName)) { continue; } isReadOnly = this.IntegratedSecurity; } Attribute[] attributesFromCollection = base.GetAttributesFromCollection(descriptor.Attributes); DbConnectionStringBuilderDescriptor descriptor2 = new DbConnectionStringBuilderDescriptor(descriptor.Name, descriptor.ComponentType, descriptor.PropertyType, isReadOnly, attributesFromCollection); descriptor2.RefreshOnChange = flag2; propertyDescriptors[displayName] = descriptor2; } base.GetProperties(propertyDescriptors); } public override bool Remove(string keyword) { Keywords keywords; ADP.CheckArgumentNull(keyword, "keyword"); if (_keywords.TryGetValue(keyword, out keywords) && base.Remove(_validKeywords[(int)keywords])) { this.Reset(keywords); return true; } return false; } private void Reset(Keywords index) { switch (index) { case Keywords.DataSource: this._dataSource = ""; return; case Keywords.FailoverPartner: this._failoverPartner = ""; return; case Keywords.AttachDBFilename: this._attachDBFilename = ""; return; case Keywords.InitialCatalog: this._initialCatalog = ""; return; case Keywords.IntegratedSecurity: this._integratedSecurity = false; return; case Keywords.PersistSecurityInfo: this._persistSecurityInfo = false; return; case Keywords.UserID: this._userID = ""; return; case Keywords.Password: this._password = ""; return; case Keywords.Enlist: this._enlist = true; return; case Keywords.Pooling: this._pooling = true; return; case Keywords.MinPoolSize: this._minPoolSize = 0; return; case Keywords.MaxPoolSize: this._maxPoolSize = 100; return; case Keywords.AsynchronousProcessing: this._asynchronousProcessing = false; return; case Keywords.ConnectionReset: this._connectionReset = true; return; case Keywords.MultipleActiveResultSets: this._multipleActiveResultSets = false; return; case Keywords.Replication: this._replication = false; return; case Keywords.ConnectTimeout: this._connectTimeout = 15; return; case Keywords.Encrypt: this._encrypt = false; return; case Keywords.TrustServerCertificate: this._trustServerCertificate = false; return; case Keywords.LoadBalanceTimeout: this._loadBalanceTimeout = 0; return; case Keywords.NetworkLibrary: this._networkLibrary = ""; return; case Keywords.PacketSize: this._packetSize = 0x1f40; return; case Keywords.TypeSystemVersion: this._typeSystemVersion = "Latest"; return; case Keywords.ApplicationName: this._applicationName = ".Net SqlClient Data Provider"; return; case Keywords.CurrentLanguage: this._currentLanguage = ""; return; case Keywords.WorkstationID: this._workstationID = ""; return; case Keywords.UserInstance: this._userInstance = false; return; case Keywords.ContextConnection: this._contextConnection = false; return; case Keywords.TransactionBinding: this._transactionBinding = "Implicit Unbind"; return; case Keywords.ApplicationIntent: this._applicationIntent = ApplicationIntent.ReadWrite; return; case Keywords.MultiSubnetFailover: this._multiSubnetFailover = false; return; } throw ADP.KeywordNotSupported(_validKeywords[(int)index]); } private void SetApplicationIntentValue(ApplicationIntent value) { base["ApplicationIntent"] = DbConnectionStringBuilderUtil.ApplicationIntentToString(value); } private void SetValue(string keyword, bool value) { base[keyword] = value.ToString(null); } private void SetValue(string keyword, int value) { base[keyword] = value.ToString((IFormatProvider)null); } private void SetValue(string keyword, string value) { ADP.CheckArgumentNull(value, keyword); base[keyword] = value; } public override bool ShouldSerialize(string keyword) { Keywords keywords; ADP.CheckArgumentNull(keyword, "keyword"); return (_keywords.TryGetValue(keyword, out keywords) && base.ShouldSerialize(_validKeywords[(int)keywords])); } public override bool TryGetValue(string keyword, out object value) { Keywords keywords; if (_keywords.TryGetValue(keyword, out keywords)) { value = this.GetAt(keywords); return true; } value = null; return false; } // Properties [ResCategory("DataCategory_Initialization"), DisplayName("ApplicationIntent"), ResDescription("DbConnectionString_ApplicationIntent"), RefreshProperties(RefreshProperties.All)] public ApplicationIntent ApplicationIntent { get { return this._applicationIntent; } set { if (!DbConnectionStringBuilderUtil.IsValidApplicationIntentValue(value)) { throw ADP.InvalidEnumerationValue(typeof(ApplicationIntent), (int)value); } this.SetApplicationIntentValue(value); this._applicationIntent = value; } } [RefreshProperties(RefreshProperties.All), DisplayName("Application Name"), ResCategory("DataCategory_Context"), ResDescription("DbConnectionString_ApplicationName")] public string ApplicationName { get { return this._applicationName; } set { this.SetValue("Application Name", value); this._applicationName = value; } } [DisplayName("Asynchronous Processing"), ResCategory("DataCategory_Initialization"), ResDescription("DbConnectionString_AsynchronousProcessing"), RefreshProperties(RefreshProperties.All)] public bool AsynchronousProcessing { get { return this._asynchronousProcessing; } set { this.SetValue("Asynchronous Processing", value); this._asynchronousProcessing = value; } } [Editor("System.Windows.Forms.Design.FileNameEditor, System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a", "System.Drawing.Design.UITypeEditor, System.Drawing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"), DisplayName("AttachDbFilename"), ResCategory("DataCategory_Source"), ResDescription("DbConnectionString_AttachDBFilename"), RefreshProperties(RefreshProperties.All)] public string AttachDBFilename { get { return this._attachDBFilename; } set { this.SetValue("AttachDbFilename", value); this._attachDBFilename = value; } } [ResCategory("DataCategory_Pooling"), Browsable(false), DisplayName("Connection Reset"), Obsolete("ConnectionReset has been deprecated. SqlConnection will ignore the 'connection reset' keyword and always reset the connection"), ResDescription("DbConnectionString_ConnectionReset"), RefreshProperties(RefreshProperties.All)] public bool ConnectionReset { get { return this._connectionReset; } set { this.SetValue("Connection Reset", value); this._connectionReset = value; } } [ResCategory("DataCategory_Initialization"), DisplayName("Connect Timeout"), RefreshProperties(RefreshProperties.All), ResDescription("DbConnectionString_ConnectTimeout")] public int ConnectTimeout { get { return this._connectTimeout; } set { if (value < 0) { throw ADP.InvalidConnectionOptionValue("Connect Timeout"); } this.SetValue("Connect Timeout", value); this._connectTimeout = value; } } [ResDescription("DbConnectionString_ContextConnection"), RefreshProperties(RefreshProperties.All), ResCategory("DataCategory_Source"), DisplayName("Context Connection")] public bool ContextConnection { get { return this._contextConnection; } set { this.SetValue("Context Connection", value); this._contextConnection = value; } } [RefreshProperties(RefreshProperties.All), DisplayName("Current Language"), ResCategory("DataCategory_Initialization"), ResDescription("DbConnectionString_CurrentLanguage")] public string CurrentLanguage { get { return this._currentLanguage; } set { this.SetValue("Current Language", value); this._currentLanguage = value; } } [ResDescription("DbConnectionString_DataSource"), DisplayName("Data Source"), RefreshProperties(RefreshProperties.All), TypeConverter(typeof(SqlDataSourceConverter)), ResCategory("DataCategory_Source")] public string DataSource { get { return this._dataSource; } set { this.SetValue("Data Source", value); this._dataSource = value; } } [ResCategory("DataCategory_Security"), ResDescription("DbConnectionString_Encrypt"), RefreshProperties(RefreshProperties.All), DisplayName("Encrypt")] public bool Encrypt { get { return this._encrypt; } set { this.SetValue("Encrypt", value); this._encrypt = value; } } [ResCategory("DataCategory_Pooling"), ResDescription("DbConnectionString_Enlist"), RefreshProperties(RefreshProperties.All), DisplayName("Enlist")] public bool Enlist { get { return this._enlist; } set { this.SetValue("Enlist", value); this._enlist = value; } } [ResDescription("DbConnectionString_FailoverPartner"), ResCategory("DataCategory_Source"), RefreshProperties(RefreshProperties.All), TypeConverter(typeof(SqlDataSourceConverter)), DisplayName("Failover Partner")] public string FailoverPartner { get { return this._failoverPartner; } set { this.SetValue("Failover Partner", value); this._failoverPartner = value; } } [ResCategory("DataCategory_Source"), ResDescription("DbConnectionString_InitialCatalog"), RefreshProperties(RefreshProperties.All), TypeConverter(typeof(SqlInitialCatalogConverter)), DisplayName("Initial Catalog")] public string InitialCatalog { get { return this._initialCatalog; } set { this.SetValue("Initial Catalog", value); this._initialCatalog = value; } } [DisplayName("Integrated Security"), ResCategory("DataCategory_Security"), ResDescription("DbConnectionString_IntegratedSecurity"), RefreshProperties(RefreshProperties.All)] public bool IntegratedSecurity { get { return this._integratedSecurity; } set { this.SetValue("Integrated Security", value); this._integratedSecurity = value; } } public override bool IsFixedSize { get { return true; } } public override object this[string keyword] { get { Keywords index = this.GetIndex(keyword); return this.GetAt(index); } set { if (value != null) { switch (this.GetIndex(keyword)) { case Keywords.DataSource: this.DataSource = ConvertToString(value); return; case Keywords.FailoverPartner: this.FailoverPartner = ConvertToString(value); return; case Keywords.AttachDBFilename: this.AttachDBFilename = ConvertToString(value); return; case Keywords.InitialCatalog: this.InitialCatalog = ConvertToString(value); return; case Keywords.IntegratedSecurity: this.IntegratedSecurity = ConvertToIntegratedSecurity(value); return; case Keywords.PersistSecurityInfo: this.PersistSecurityInfo = ConvertToBoolean(value); return; case Keywords.UserID: this.UserID = ConvertToString(value); return; case Keywords.Password: this.Password = ConvertToString(value); return; case Keywords.Enlist: this.Enlist = ConvertToBoolean(value); return; case Keywords.Pooling: this.Pooling = ConvertToBoolean(value); return; case Keywords.MinPoolSize: this.MinPoolSize = ConvertToInt32(value); return; case Keywords.MaxPoolSize: this.MaxPoolSize = ConvertToInt32(value); return; case Keywords.AsynchronousProcessing: this.AsynchronousProcessing = ConvertToBoolean(value); return; case Keywords.ConnectionReset: this.ConnectionReset = ConvertToBoolean(value); return; case Keywords.MultipleActiveResultSets: this.MultipleActiveResultSets = ConvertToBoolean(value); return; case Keywords.Replication: this.Replication = ConvertToBoolean(value); return; case Keywords.ConnectTimeout: this.ConnectTimeout = ConvertToInt32(value); return; case Keywords.Encrypt: this.Encrypt = ConvertToBoolean(value); return; case Keywords.TrustServerCertificate: this.TrustServerCertificate = ConvertToBoolean(value); return; case Keywords.LoadBalanceTimeout: this.LoadBalanceTimeout = ConvertToInt32(value); return; case Keywords.NetworkLibrary: this.NetworkLibrary = ConvertToString(value); return; case Keywords.PacketSize: this.PacketSize = ConvertToInt32(value); return; case Keywords.TypeSystemVersion: this.TypeSystemVersion = ConvertToString(value); return; case Keywords.ApplicationName: this.ApplicationName = ConvertToString(value); return; case Keywords.CurrentLanguage: this.CurrentLanguage = ConvertToString(value); return; case Keywords.WorkstationID: this.WorkstationID = ConvertToString(value); return; case Keywords.UserInstance: this.UserInstance = ConvertToBoolean(value); return; case Keywords.ContextConnection: this.ContextConnection = ConvertToBoolean(value); return; case Keywords.TransactionBinding: this.TransactionBinding = ConvertToString(value); return; case Keywords.ApplicationIntent: this.ApplicationIntent = ConvertToApplicationIntent(keyword, value); return; case Keywords.MultiSubnetFailover: this.MultiSubnetFailover = ConvertToBoolean(value); return; } throw ADP.KeywordNotSupported(keyword); } this.Remove(keyword); } } public override ICollection Keys { get { return new ReadOnlyCollection<string>(_validKeywords); } } [DisplayName("Load Balance Timeout"), ResDescription("DbConnectionString_LoadBalanceTimeout"), RefreshProperties(RefreshProperties.All), ResCategory("DataCategory_Pooling")] public int LoadBalanceTimeout { get { return this._loadBalanceTimeout; } set { if (value < 0) { throw ADP.InvalidConnectionOptionValue("Load Balance Timeout"); } this.SetValue("Load Balance Timeout", value); this._loadBalanceTimeout = value; } } [DisplayName("Max Pool Size"), ResCategory("DataCategory_Pooling"), ResDescription("DbConnectionString_MaxPoolSize"), RefreshProperties(RefreshProperties.All)] public int MaxPoolSize { get { return this._maxPoolSize; } set { if (value < 1) { throw ADP.InvalidConnectionOptionValue("Max Pool Size"); } this.SetValue("Max Pool Size", value); this._maxPoolSize = value; } } [ResDescription("DbConnectionString_MinPoolSize"), RefreshProperties(RefreshProperties.All), ResCategory("DataCategory_Pooling"), DisplayName("Min Pool Size")] public int MinPoolSize { get { return this._minPoolSize; } set { if (value < 0) { throw ADP.InvalidConnectionOptionValue("Min Pool Size"); } this.SetValue("Min Pool Size", value); this._minPoolSize = value; } } [DisplayName("MultipleActiveResultSets"), RefreshProperties(RefreshProperties.All), ResCategory("DataCategory_Advanced"), ResDescription("DbConnectionString_MultipleActiveResultSets")] public bool MultipleActiveResultSets { get { return this._multipleActiveResultSets; } set { this.SetValue("MultipleActiveResultSets", value); this._multipleActiveResultSets = value; } } [ResDescription("DbConnectionString_MultiSubnetFailover"), DisplayName("MultiSubnetFailover"), ResCategory("DataCategory_Source"), RefreshProperties(RefreshProperties.All)] public bool MultiSubnetFailover { get { return this._multiSubnetFailover; } set { this.SetValue("MultiSubnetFailover", value); this._multiSubnetFailover = value; } } [ResCategory("DataCategory_Advanced"), DisplayName("Network Library"), TypeConverter(typeof(NetworkLibraryConverter)), ResDescription("DbConnectionString_NetworkLibrary"), RefreshProperties(RefreshProperties.All)] public string NetworkLibrary { get { return this._networkLibrary; } set { if (value != null) { switch (value.Trim().ToLower(CultureInfo.InvariantCulture)) { case "dbmsadsn": value = "dbmsadsn"; goto Label_011F; case "dbmsvinn": value = "dbmsvinn"; goto Label_011F; case "dbmsspxn": value = "dbmsspxn"; goto Label_011F; case "dbmsrpcn": value = "dbmsrpcn"; goto Label_011F; case "dbnmpntw": value = "dbnmpntw"; goto Label_011F; case "dbmslpcn": value = "dbmslpcn"; goto Label_011F; case "dbmssocn": value = "dbmssocn"; goto Label_011F; case "dbmsgnet": value = "dbmsgnet"; goto Label_011F; } throw ADP.InvalidConnectionOptionValue("Network Library"); } Label_011F: this.SetValue("Network Library", value); this._networkLibrary = value; } } [ResCategory("DataCategory_Advanced"), RefreshProperties(RefreshProperties.All), ResDescription("DbConnectionString_PacketSize"), DisplayName("Packet Size")] public int PacketSize { get { return this._packetSize; } set { if ((value < 0x200) || (0x8000 < value)) { throw SQL.InvalidPacketSizeValue(); } this.SetValue("Packet Size", value); this._packetSize = value; } } [PasswordPropertyText(true), DisplayName("Password"), ResDescription("DbConnectionString_Password"), RefreshProperties(RefreshProperties.All), ResCategory("DataCategory_Security")] public string Password { get { return this._password; } set { this.SetValue("Password", value); this._password = value; } } [ResDescription("DbConnectionString_PersistSecurityInfo"), RefreshProperties(RefreshProperties.All), ResCategory("DataCategory_Security"), DisplayName("Persist Security Info")] public bool PersistSecurityInfo { get { return this._persistSecurityInfo; } set { this.SetValue("Persist Security Info", value); this._persistSecurityInfo = value; } } [ResDescription("DbConnectionString_Pooling"), RefreshProperties(RefreshProperties.All), DisplayName("Pooling"), ResCategory("DataCategory_Pooling")] public bool Pooling { get { return this._pooling; } set { this.SetValue("Pooling", value); this._pooling = value; } } [DisplayName("Replication"), ResDescription("DbConnectionString_Replication"), ResCategory("DataCategory_Replication"), RefreshProperties(RefreshProperties.All)] public bool Replication { get { return this._replication; } set { this.SetValue("Replication", value); this._replication = value; } } [ResCategory("DataCategory_Advanced"), ResDescription("DbConnectionString_TransactionBinding"), DisplayName("Transaction Binding"), RefreshProperties(RefreshProperties.All)] public string TransactionBinding { get { return this._transactionBinding; } set { this.SetValue("Transaction Binding", value); this._transactionBinding = value; } } [ResDescription("DbConnectionString_TrustServerCertificate"), ResCategory("DataCategory_Security"), RefreshProperties(RefreshProperties.All), DisplayName("TrustServerCertificate")] public bool TrustServerCertificate { get { return this._trustServerCertificate; } set { this.SetValue("TrustServerCertificate", value); this._trustServerCertificate = value; } } [ResDescription("DbConnectionString_TypeSystemVersion"), ResCategory("DataCategory_Advanced"), RefreshProperties(RefreshProperties.All), DisplayName("Type System Version")] public string TypeSystemVersion { get { return this._typeSystemVersion; } set { this.SetValue("Type System Version", value); this._typeSystemVersion = value; } } [ResCategory("DataCategory_Security"), RefreshProperties(RefreshProperties.All), ResDescription("DbConnectionString_UserID"), DisplayName("User ID")] public string UserID { get { return this._userID; } set { this.SetValue("User ID", value); this._userID = value; } } [RefreshProperties(RefreshProperties.All), ResDescription("DbConnectionString_UserInstance"), DisplayName("User Instance"), ResCategory("DataCategory_Source")] public bool UserInstance { get { return this._userInstance; } set { this.SetValue("User Instance", value); this._userInstance = value; } } public override ICollection Values { get { object[] items = new object[_validKeywords.Length]; for (int i = 0; i < items.Length; i++) { items[i] = this.GetAt((Keywords)i); } return new ReadOnlyCollection<object>(items); } } [ResDescription("DbConnectionString_WorkstationID"), DisplayName("Workstation ID"), RefreshProperties(RefreshProperties.All), ResCategory("DataCategory_Context")] public string WorkstationID { get { return this._workstationID; } set { this.SetValue("Workstation ID", value); this._workstationID = value; } } // Nested Types private enum Keywords { DataSource, FailoverPartner, AttachDBFilename, InitialCatalog, IntegratedSecurity, PersistSecurityInfo, UserID, Password, Enlist, Pooling, MinPoolSize, MaxPoolSize, AsynchronousProcessing, ConnectionReset, MultipleActiveResultSets, Replication, ConnectTimeout, Encrypt, TrustServerCertificate, LoadBalanceTimeout, NetworkLibrary, PacketSize, TypeSystemVersion, ApplicationName, CurrentLanguage, WorkstationID, UserInstance, ContextConnection, TransactionBinding, ApplicationIntent, MultiSubnetFailover, KeywordsCount } private sealed class NetworkLibraryConverter : TypeConverter { // Fields private TypeConverter.StandardValuesCollection _standardValues; private const string NamedPipes = "Named Pipes (DBNMPNTW)"; private const string SharedMemory = "Shared Memory (DBMSLPCN)"; private const string TCPIP = "TCP/IP (DBMSSOCN)"; private const string VIA = "VIA (DBMSGNET)"; // Methods public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType) { if (!(typeof(string) == sourceType)) { return base.CanConvertFrom(context, sourceType); } return true; } public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType) { if (!(typeof(string) == destinationType)) { return base.CanConvertTo(context, destinationType); } return true; } public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value) { string x = value as string; if (x == null) { return base.ConvertFrom(context, culture, value); } x = x.Trim(); if (StringComparer.OrdinalIgnoreCase.Equals(x, "Named Pipes (DBNMPNTW)")) { return "dbnmpntw"; } if (StringComparer.OrdinalIgnoreCase.Equals(x, "Shared Memory (DBMSLPCN)")) { return "dbmslpcn"; } if (StringComparer.OrdinalIgnoreCase.Equals(x, "TCP/IP (DBMSSOCN)")) { return "dbmssocn"; } if (StringComparer.OrdinalIgnoreCase.Equals(x, "VIA (DBMSGNET)")) { return "dbmsgnet"; } return x; } public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType) { string str2 = value as string; if ((str2 == null) || !(destinationType == typeof(string))) { return base.ConvertTo(context, culture, value, destinationType); } string str = str2.Trim().ToLower(CultureInfo.InvariantCulture); if (str == null) { return str2; } if (!(str == "dbnmpntw")) { if (str == "dbmslpcn") { return "Shared Memory (DBMSLPCN)"; } if (str == "dbmssocn") { return "TCP/IP (DBMSSOCN)"; } if (str == "dbmsgnet") { return "VIA (DBMSGNET)"; } return str2; } return "Named Pipes (DBNMPNTW)"; } public override TypeConverter.StandardValuesCollection GetStandardValues(ITypeDescriptorContext context) { if (context != null) { object instance = context.Instance; } TypeConverter.StandardValuesCollection valuess = this._standardValues; if (valuess == null) { string[] values = new string[] { "Named Pipes (DBNMPNTW)", "Shared Memory (DBMSLPCN)", "TCP/IP (DBMSSOCN)", "VIA (DBMSGNET)" }; valuess = new TypeConverter.StandardValuesCollection(values); this._standardValues = valuess; } return valuess; } public override bool GetStandardValuesExclusive(ITypeDescriptorContext context) { return false; } public override bool GetStandardValuesSupported(ITypeDescriptorContext context) { return true; } } internal sealed class SqlConnectionStringBuilderConverter : ExpandableObjectConverter { // Methods public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType) { return ((typeof(InstanceDescriptor) == destinationType) || base.CanConvertTo(context, destinationType)); } public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType) { if (destinationType == null) { throw ADP.ArgumentNull("destinationType"); } if (typeof(InstanceDescriptor) == destinationType) { SqlConnectionStringBuilder options = value as SqlConnectionStringBuilder; if (options != null) { return this.ConvertToInstanceDescriptor(options); } } return base.ConvertTo(context, culture, value, destinationType); } private InstanceDescriptor ConvertToInstanceDescriptor(SqlConnectionStringBuilder options) { Type[] types = new Type[] { typeof(string) }; return new InstanceDescriptor(typeof(SqlConnectionStringBuilder).GetConstructor(types), new object[] { options.ConnectionString }); } } private sealed class SqlDataSourceConverter : StringConverter { // Fields private TypeConverter.StandardValuesCollection _standardValues; // Methods public override TypeConverter.StandardValuesCollection GetStandardValues(ITypeDescriptorContext context) { TypeConverter.StandardValuesCollection valuess = this._standardValues; if (this._standardValues == null) { DataTable dataSources = SqlClientFactory.Instance.CreateDataSourceEnumerator().GetDataSources(); DataColumn column2 = dataSources.Columns["ServerName"]; DataColumn column = dataSources.Columns["InstanceName"]; DataRowCollection rows = dataSources.Rows; string[] array = new string[rows.Count]; for (int i = 0; i < array.Length; i++) { string str2 = rows[i][column2] as string; string str = rows[i][column] as string; if (((str == null) || (str.Length == 0)) || ("MSSQLSERVER" == str)) { array[i] = str2; } else { array[i] = str2 + @"\" + str; } } Array.Sort<string>(array); valuess = new TypeConverter.StandardValuesCollection(array); this._standardValues = valuess; } return valuess; } public override bool GetStandardValuesExclusive(ITypeDescriptorContext context) { return false; } public override bool GetStandardValuesSupported(ITypeDescriptorContext context) { return true; } } private sealed class SqlInitialCatalogConverter : StringConverter { // Methods public override TypeConverter.StandardValuesCollection GetStandardValues(ITypeDescriptorContext context) { if (!this.GetStandardValuesSupportedInternal(context)) { return null; } List<string> values = new List<string>(); try { SqlConnectionStringBuilder instance = (SqlConnectionStringBuilder)context.Instance; using (SqlConnection connection = new SqlConnection()) { connection.ConnectionString = instance.ConnectionString; connection.Open(); foreach (DataRow row in connection.GetSchema("DATABASES").Rows) { string item = (string)row["database_name"]; values.Add(item); } } } catch (SqlException exception) { ADP.TraceExceptionWithoutRethrow(exception); } return new TypeConverter.StandardValuesCollection(values); } public override bool GetStandardValuesExclusive(ITypeDescriptorContext context) { return false; } public override bool GetStandardValuesSupported(ITypeDescriptorContext context) { return this.GetStandardValuesSupportedInternal(context); } private bool GetStandardValuesSupportedInternal(ITypeDescriptorContext context) { bool flag = false; if (context == null) { return flag; } SqlConnectionStringBuilder instance = context.Instance as SqlConnectionStringBuilder; if (((instance == null) || (0 >= instance.DataSource.Length)) || (!instance.IntegratedSecurity && (0 >= instance.UserID.Length))) { return flag; } return true; } } }发现这个类是继承类：DbConnectionStringBuilder
那么，在看看这个类的源代码：
public class DbConnectionStringBuilder : IDictionary, ICollection, IEnumerable, ICustomTypeDescriptor{ // Fields private bool _browsableConnectionString; private string _connectionString; private Dictionary<string, object> _currentValues; internal readonly int _objectID; private static int _objectTypeCount; private PropertyDescriptorCollection _propertyDescriptors; private readonly bool UseOdbcRules; // Methods public DbConnectionStringBuilder() { this._connectionString = ""; this._browsableConnectionString = true; this._objectID = Interlocked.Increment(ref _objectTypeCount); } public DbConnectionStringBuilder(bool useOdbcRules) { this._connectionString = ""; this._browsableConnectionString = true; this._objectID = Interlocked.Increment(ref _objectTypeCount); this.UseOdbcRules = useOdbcRules; } public void Add(string keyword, object value) { this[keyword] = value; } public static void AppendKeyValuePair(StringBuilder builder, string keyword, string value) { DbConnectionOptions.AppendKeyValuePairBuilder(builder, keyword, value, false); } public static void AppendKeyValuePair(StringBuilder builder, string keyword, string value, bool useOdbcRules) { DbConnectionOptions.AppendKeyValuePairBuilder(builder, keyword, value, useOdbcRules); } public virtual void Clear() { Bid.Trace("<comm.DbConnectionStringBuilder.Clear|API>\n"); this._connectionString = ""; this._propertyDescriptors = null; this.CurrentValues.Clear(); } protected internal void ClearPropertyDescriptors() { this._propertyDescriptors = null; } public virtual bool ContainsKey(string keyword) { ADP.CheckArgumentNull(keyword, "keyword"); return this.CurrentValues.ContainsKey(keyword); } public virtual bool EquivalentTo(DbConnectionStringBuilder connectionStringBuilder) { ADP.CheckArgumentNull(connectionStringBuilder, "connectionStringBuilder"); Bid.Trace("<comm.DbConnectionStringBuilder.EquivalentTo|API> %d#, connectionStringBuilder=%d#\n", this.ObjectID, connectionStringBuilder.ObjectID); if ((base.GetType() != connectionStringBuilder.GetType()) || (this.CurrentValues.Count != connectionStringBuilder.CurrentValues.Count)) { return false; } foreach (KeyValuePair<string, object> pair in this.CurrentValues) { object obj2; if (!connectionStringBuilder.CurrentValues.TryGetValue(pair.Key, out obj2) || !pair.Value.Equals(obj2)) { return false; } } return true; } internal Attribute[] GetAttributesFromCollection(AttributeCollection collection) { Attribute[] array = new Attribute[collection.Count]; collection.CopyTo(array, 0); return array; } private PropertyDescriptorCollection GetProperties() { PropertyDescriptorCollection descriptors = this._propertyDescriptors; if (descriptors == null) { IntPtr ptr; Bid.ScopeEnter(out ptr, "<comm.DbConnectionStringBuilder.GetProperties|INFO> %d#", this.ObjectID); try { Hashtable propertyDescriptors = new Hashtable(StringComparer.OrdinalIgnoreCase); this.GetProperties(propertyDescriptors); PropertyDescriptor[] array = new PropertyDescriptor[propertyDescriptors.Count]; propertyDescriptors.Values.CopyTo(array, 0); descriptors = new PropertyDescriptorCollection(array); this._propertyDescriptors = descriptors; } finally { Bid.ScopeLeave(ref ptr); } } return descriptors; } protected virtual void GetProperties(Hashtable propertyDescriptors) { IntPtr ptr; Bid.ScopeEnter(out ptr, "<comm.DbConnectionStringBuilder.GetProperties|API> %d#", this.ObjectID); try { Attribute[] attributesFromCollection; foreach (PropertyDescriptor descriptor in TypeDescriptor.GetProperties(this, true)) { if ("ConnectionString" != descriptor.Name) { string displayName = descriptor.DisplayName; if (!propertyDescriptors.ContainsKey(displayName)) { attributesFromCollection = this.GetAttributesFromCollection(descriptor.Attributes); PropertyDescriptor descriptor3 = new DbConnectionStringBuilderDescriptor(descriptor.Name, descriptor.ComponentType, descriptor.PropertyType, descriptor.IsReadOnly, attributesFromCollection); propertyDescriptors[displayName] = descriptor3; } } else { if (this.BrowsableConnectionString) { propertyDescriptors["ConnectionString"] = descriptor; continue; } propertyDescriptors.Remove("ConnectionString"); } } if (!this.IsFixedSize) { attributesFromCollection = null; foreach (string str in this.Keys) { Type type; if (propertyDescriptors.ContainsKey(str)) { continue; } object obj2 = this[str]; if (obj2 != null) { type = obj2.GetType(); if (typeof(string) == type) { int num; if (int.TryParse((string) obj2, out num)) { type = typeof(int); } else { bool flag; if (bool.TryParse((string) obj2, out flag)) { type = typeof(bool); } } } } else { type = typeof(string); } Attribute[] attributes = attributesFromCollection; if (StringComparer.OrdinalIgnoreCase.Equals("Password", str) || StringComparer.OrdinalIgnoreCase.Equals("pwd", str)) { attributes = new Attribute[] { BrowsableAttribute.Yes, PasswordPropertyTextAttribute.Yes, new ResCategoryAttribute("DataCategory_Security"), RefreshPropertiesAttribute.All }; } else if (attributesFromCollection == null) { attributesFromCollection = new Attribute[] { BrowsableAttribute.Yes, RefreshPropertiesAttribute.All }; attributes = attributesFromCollection; } PropertyDescriptor descriptor2 = new DbConnectionStringBuilderDescriptor(str, base.GetType(), type, false, attributes); propertyDescriptors[str] = descriptor2; } } } finally { Bid.ScopeLeave(ref ptr); } } private PropertyDescriptorCollection GetProperties(Attribute[] attributes) { PropertyDescriptorCollection properties = this.GetProperties(); if ((attributes == null) || (attributes.Length == 0)) { return properties; } PropertyDescriptor[] sourceArray = new PropertyDescriptor[properties.Count]; int index = 0; foreach (PropertyDescriptor descriptor in properties) { bool flag = true; foreach (Attribute attribute in attributes) { Attribute attribute2 = descriptor.Attributes[attribute.GetType()]; if (((attribute2 == null) && !attribute.IsDefaultAttribute()) || !attribute2.Match(attribute)) { flag = false; break; } } if (flag) { sourceArray[index] = descriptor; index++; } } PropertyDescriptor[] destinationArray = new PropertyDescriptor[index]; Array.Copy(sourceArray, destinationArray, index); return new PropertyDescriptorCollection(destinationArray); } private string ObjectToString(object keyword) { string str; try { str = (string) keyword; } catch (InvalidCastException) { throw new ArgumentException("keyword", "not a string"); } return str; } public virtual bool Remove(string keyword) { Bid.Trace("<comm.DbConnectionStringBuilder.Remove|API> %d#, keyword='%ls'\n", this.ObjectID, keyword); ADP.CheckArgumentNull(keyword, "keyword"); if (this.CurrentValues.Remove(keyword)) { this._connectionString = null; this._propertyDescriptors = null; return true; } return false; } public virtual bool ShouldSerialize(string keyword) { ADP.CheckArgumentNull(keyword, "keyword"); return this.CurrentValues.ContainsKey(keyword); } void ICollection.CopyTo(Array array, int index) { Bid.Trace("<comm.DbConnectionStringBuilder.ICollection.CopyTo|API> %d#\n", this.ObjectID); this.Collection.CopyTo(array, index); } void IDictionary.Add(object keyword, object value) { this.Add(this.ObjectToString(keyword), value); } bool IDictionary.Contains(object keyword) { return this.ContainsKey(this.ObjectToString(keyword)); } IDictionaryEnumerator IDictionary.GetEnumerator() { Bid.Trace("<comm.DbConnectionStringBuilder.IDictionary.GetEnumerator|API> %d#\n", this.ObjectID); return this.Dictionary.GetEnumerator(); } void IDictionary.Remove(object keyword) { this.Remove(this.ObjectToString(keyword)); } IEnumerator IEnumerable.GetEnumerator() { Bid.Trace("<comm.DbConnectionStringBuilder.IEnumerable.GetEnumerator|API> %d#\n", this.ObjectID); return this.Collection.GetEnumerator(); } AttributeCollection ICustomTypeDescriptor.GetAttributes() { return TypeDescriptor.GetAttributes(this, true); } string ICustomTypeDescriptor.GetClassName() { return TypeDescriptor.GetClassName(this, true); } string ICustomTypeDescriptor.GetComponentName() { return TypeDescriptor.GetComponentName(this, true); } TypeConverter ICustomTypeDescriptor.GetConverter() { return TypeDescriptor.GetConverter(this, true); } EventDescriptor ICustomTypeDescriptor.GetDefaultEvent() { return TypeDescriptor.GetDefaultEvent(this, true); } PropertyDescriptor ICustomTypeDescriptor.GetDefaultProperty() { return TypeDescriptor.GetDefaultProperty(this, true); } object ICustomTypeDescriptor.GetEditor(Type editorBaseType) { return TypeDescriptor.GetEditor(this, editorBaseType, true); } EventDescriptorCollection ICustomTypeDescriptor.GetEvents() { return TypeDescriptor.GetEvents(this, true); } EventDescriptorCollection ICustomTypeDescriptor.GetEvents(Attribute[] attributes) { return TypeDescriptor.GetEvents(this, attributes, true); } PropertyDescriptorCollection ICustomTypeDescriptor.GetProperties() { return this.GetProperties(); } PropertyDescriptorCollection ICustomTypeDescriptor.GetProperties(Attribute[] attributes) { return this.GetProperties(attributes); } object ICustomTypeDescriptor.GetPropertyOwner(PropertyDescriptor pd) { return this; } public override string ToString() { return this.ConnectionString; } public virtual bool TryGetValue(string keyword, out object value) { ADP.CheckArgumentNull(keyword, "keyword"); return this.CurrentValues.TryGetValue(keyword, out value); } // Properties [DesignOnly(true), DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden), Browsable(false), EditorBrowsable(EditorBrowsableState.Never)] public bool BrowsableConnectionString { get { return this._browsableConnectionString; } set { this._browsableConnectionString = value; this._propertyDescriptors = null; } } private ICollection Collection { get { return this.CurrentValues; } } [RefreshProperties(RefreshProperties.All), ResDescription("DbConnectionString_ConnectionString"), ResCategory("DataCategory_Data")] public string ConnectionString { get { Bid.Trace("<comm.DbConnectionStringBuilder.get_ConnectionString|API> %d#\n", this.ObjectID); string str = this._connectionString; if (str == null) { StringBuilder builder = new StringBuilder(); foreach (string str2 in this.Keys) { object obj2; if (this.ShouldSerialize(str2) && this.TryGetValue(str2, out obj2)) { string str3 = (obj2 != null) ? Convert.ToString(obj2, CultureInfo.InvariantCulture) : null; AppendKeyValuePair(builder, str2, str3, this.UseOdbcRules); } } str = builder.ToString(); this._connectionString = str; } return str; } set { Bid.Trace("<comm.DbConnectionStringBuilder.set_ConnectionString|API> %d#\n", this.ObjectID); DbConnectionOptions options = new DbConnectionOptions(value, null, this.UseOdbcRules); string connectionString = this.ConnectionString; this.Clear(); try { for (NameValuePair pair = options.KeyChain; pair != null; pair = pair.Next) { if (pair.Value != null) { this[pair.Name] = pair.Value; } else { this.Remove(pair.Name); } } this._connectionString = null; } catch (ArgumentException) { this.ConnectionString = connectionString; this._connectionString = connectionString; throw; } } } [Browsable(false)] public virtual int Count { get { return this.CurrentValues.Count; } } private Dictionary<string, object> CurrentValues { get { Dictionary<string, object> dictionary = this._currentValues; if (dictionary == null) { dictionary = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase); this._currentValues = dictionary; } return dictionary; } } private IDictionary Dictionary { get { return this.CurrentValues; } } [Browsable(false)] public virtual bool IsFixedSize { get { return false; } } [Browsable(false)] public bool IsReadOnly { get { return false; } } [Browsable(false)] public virtual object this[string keyword] { get { object obj2; Bid.Trace("<comm.DbConnectionStringBuilder.get_Item|API> %d#, keyword='%ls'\n", this.ObjectID, keyword); ADP.CheckArgumentNull(keyword, "keyword"); if (!this.CurrentValues.TryGetValue(keyword, out obj2)) { throw ADP.KeywordNotSupported(keyword); } return obj2; } set { ADP.CheckArgumentNull(keyword, "keyword"); bool flag = false; if (value != null) { string str = DbConnectionStringBuilderUtil.ConvertToString(value); DbConnectionOptions.ValidateKeyValuePair(keyword, str); flag = this.CurrentValues.ContainsKey(keyword); this.CurrentValues[keyword] = str; } else { flag = this.Remove(keyword); } this._connectionString = null; if (flag) { this._propertyDescriptors = null; } } } [Browsable(false)] public virtual ICollection Keys { get { Bid.Trace("<comm.DbConnectionStringBuilder.Keys|API> %d#\n", this.ObjectID); return this.Dictionary.Keys; } } internal int ObjectID { get { return this._objectID; } } bool ICollection.IsSynchronized { get { return this.Collection.IsSynchronized; } } object ICollection.SyncRoot { get { return this.Collection.SyncRoot; } } object IDictionary.this[object keyword] { get { return this[this.ObjectToString(keyword)]; } set { this[this.ObjectToString(keyword)] = value; } } [Browsable(false)] public virtual ICollection Values { get { Bid.Trace("<comm.DbConnectionStringBuilder.Values|API> %d#\n", this.ObjectID); ICollection<string> keys = (ICollection<string>) this.Keys; IEnumerator<string> enumerator = keys.GetEnumerator(); object[] items = new object[keys.Count]; for (int i = 0; i < items.Length; i++) { enumerator.MoveNext(); items[i] = this[enumerator.Current]; } return new ReadOnlyCollection<object>(items); } }} Collapse Methods 关于数据库参数的配置来自于一个枚举：
private enum Keywords { DataSource,//要连接到的 SQL Server 实例的名称或网络地址 FailoverPartner,//在主服务器停机时要连接到的伙伴服务器的名称或地址 AttachDBFilename,//包含主数据文件名称的字符串。该字符串包括可附加数据库的完整路径名 InitialCatalog,//与该连接关联的数据库的名称 IntegratedSecurity,//一个布尔值，该值指示是否在连接中指定用户 ID 和密码（值为 false 时），或者是否使用当前的 Windows 帐户凭据进行身份验证（值为 true 时） PersistSecurityInfo,//一个布尔值，该值指示如果连接是打开的或者一直处于打开状态，那么安全敏感信息（如密码）是否将不作为连接的一部分返回 UserID,//连接到 SQL Server 时要使用的用户 ID Password,//SQL Server 帐户的密码 Enlist,//一个布尔值，该值指示 SQL Server 连接池程序是否在创建线程的当前事务上下文中自动登记连接 Pooling,//一个布尔值，该值指示每次请求连接时该连接是汇入连接池还是显式打开 MinPoolSize,//针对此特定连接字符串连接池中所允许的最小连接数 MaxPoolSize,//针对此特定连接字符串连接池中所允许的最大连接数 AsynchronousProcessing,//一个布尔值，该值指定使用此连接字符串创建的连接是否允许异步处理 ConnectionReset,//一个布尔值，该值指示在从连接池中提取连接时是否重置连接(已过时) MultipleActiveResultSets,//一个布尔值，该值指示多活动结果集是否可与关联的连接相关联 Replication,//一个布尔值，该值指示是否使用连接来支持复制 ConnectTimeout,//在终止尝试并产生错误之前，等待与服务器连接的时间长度（以秒为单位） Encrypt,//一个布尔值，该值指示在服务器安装了证书的情况下，SQL Server 是否为客户端和服务器之间发送的所有数据使用 SSL 加密 TrustServerCertificate,//该值指示在跳过用于验证信任的证书链遍历时是否加密信道 LoadBalanceTimeout,//连接被销毁前在连接池中存活的最短时间（以秒为单位） NetworkLibrary,//一个字符串，该字符串包含用于建立与 SQL Server 的连接的网络库的名称 PacketSize,//用来与 SQL Server 的实例通信的网络数据包的大小（以字节为单位） TypeSystemVersion,//一个字符串值，该值指示应用程序所需的类型系统 ApplicationName,//与连接字符串关联的应用程序的名称,如果未提供名称，则为“.NET SqlClient Data Provider” CurrentLanguage,//获取或设置 SQL Server 语言记录名称 WorkstationID,//连接到 SQL Server 的工作站的名称 UserInstance,//该值指示是否将连接从默认的 SQL Server Express 实例重定向到在调用方帐户之下运行并且在运行时启动的实例 ContextConnection,//该值指示应建立与 SQL Server 的客户端/服务器连接还是进程内连接 TransactionBinding,//一个字符串值，该值指示该连接如何保持与登记 System.Transactions 事务的关联 ApplicationIntent, MultiSubnetFailover, KeywordsCount }通过查看类中初始值，例如MaxPoolSize，MinPoolSize，采用默认值能够满足大多数情况，如果需要特殊处理，只需要修改连接字符串
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那么OleDB，ODBC方式，以及Oracle的连接等，其连接参数如何呢
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