.NET CsvWriter

Imports System.TextImports System.IO''' <summary>''' 快速写入数据到CSV文件''' </summary>Public Class CsvWriter#Region "Constants"    ''' <summary>    ''' Defines the default delimiter character separating each field.    ''' </summary>    Public Const DefaultDelimiter As Char = ","c    ''' <summary>    ''' Defines the default quote character wrapping every field.    ''' </summary>    Public Const DefaultQuote As Char = """"c    ''' <summary>    ''' Defines the default escape character letting insert quotation characters inside a quoted field.    ''' </summary>    Public Const DefaultEscape As Char = """"c    ''' <summary>    ''' Defines the default comment character indicating that a line is commented out.    ''' </summary>    Public Const DefaultComment As Char = "#"c#End Region#Region "Constructors"    Sub New()        Me.New(DefaultDelimiter, DefaultQuote, DefaultEscape, DefaultComment)    End Sub    Sub New(ByVal delimiter As Char)        Me.New(delimiter, DefaultQuote, DefaultEscape, DefaultComment)    End Sub    ''' <summary>    ''' Initializes a new instance of the CsvWriter class.    ''' </summary>    ''' <param name="delimiter">The delimiter character separating each field (default is ',').(分隔符号默认",")</param>    ''' <param name="quote">The quotation character wrapping every field (default is ''').(需要转义的字符串 重复出现2次)</param>    ''' <param name="escape">    ''' The escape character letting insert quotation characters inside a quoted field (default is '\').    ''' If no escape character, set to '\0' to gain some performance.(包装用)    ''' </param>    ''' <param name="comment">The comment character indicating that a line is commented out (default is '#').</param>    ''' <exception cref="T:ArgumentNullException">    '''<paramref name="reader"/> is a <see langword="null"/>.    ''' </exception>    ''' <exception cref="ArgumentOutOfRangeException">    '''<paramref name="bufferSize"/> must be 1 or more.    ''' </exception>    Sub New(ByVal delimiter As Char, ByVal quote As Char, ByVal escape As Char, ByVal comment As Char)        _delimiter = delimiter        _quote = quote        _escape = escape        _comment = comment    End Sub#End Region#Region "Write"    Public Sub Write(ByVal writer As TextWriter, ByVal table As DataTable)        Dim cols = From c As DataColumn In table.Columns Select ObjToString(c.ColumnName)        writer.WriteLine(String.Join(_delimiter, cols))        Write(writer, table.Rows)    End Sub    Public Sub Write(ByVal writer As TextWriter, ByVal rows As IList(Of String()))        For Each row In rows            Dim items() As String = (From r In row Select ObjToString(r)).ToArray            Dim str As String = String.Join(_delimiter, items)            writer.WriteLine(str)        Next    End Sub    Public Sub Write(ByVal writer As TextWriter, ByVal rows() As DataRow)        For Each row As DataRow In rows            Dim items() As String = (From o As Object In row.ItemArray Select ObjToString(o)).ToArray            Dim str As String = String.Join(_delimiter, items)            writer.WriteLine(str)        Next    End Sub    Public Sub Write(ByVal writer As TextWriter, ByVal rows As DataRowCollection)        For Each row As DataRow In rows            Dim items() As String = (From o As Object In row.ItemArray Select ObjToString(o)).ToArray            Dim str As String = String.Join(_delimiter, items)            writer.WriteLine(str)        Next    End Sub    Public Function ObjToString(ByVal obj As Object) As String        If obj Is Nothing Then Return String.Empty        Dim str As String = obj.ToString        'If str.Length > 30000 Then MsgBox(str)        If str.Contains(_delimiter) OrElse str.Contains(_quote) OrElse str.Contains(vbCr) OrElse str.Contains(vbLf) Then            Dim strb As New StringBuilder(_escape)            For Each c In str                If c = _quote Then strb.Append(_quote)                strb.Append(c)            Next            strb.Append(_escape)            Return strb.ToString        End If        Return str    End Function#End Region#Region "Fields"    ''' <summary>    ''' Contains the <see cref="T:TextReader"/> export to the CSV file.    ''' </summary>    Private _writer As TextWriter    ''' <summary>    ''' Contains the comment character indicating that a line is commented out.    ''' </summary>    Private _comment As Char    ''' <summary>    ''' Contains the escape character letting insert quotation characters inside a quoted field.    ''' </summary>    Private _escape As Char    ''' <summary>    ''' Contains the delimiter character separating each field.    ''' </summary>    Private _delimiter As Char    ''' <summary>    ''' Contains the quotation character wrapping every field.    ''' </summary>    Private _quote As Char    ''' <summary>    ''' Indicates if the reader supports multiline.    ''' </summary>    Private _supportsMultiline As Boolean    ''' <summary>    ''' Indicates if the reader will skip empty lines.    ''' </summary>    Private _skipEmptyLines As Boolean#End Region#Region "Properties"    ''' <summary>    ''' Gets the comment character indicating that a line is commented out.    ''' </summary>    ''' <value>The comment character indicating that a line is commented out.</value>    Public ReadOnly Property Comment As Char        Get            Return _comment        End Get    End Property    ''' <summary>    ''' Gets the escape character letting insert quotation characters inside a quoted field.    ''' </summary>    ''' <value>The escape character letting insert quotation characters inside a quoted field.</value>    Public ReadOnly Property Escape As Char        Get            Return _escape        End Get    End Property    ''' <summary>    ''' Gets the delimiter character separating each field.    ''' </summary>    ''' <value>The delimiter character separating each field.</value>    Public ReadOnly Property Delimiter As Char        Get            Return _delimiter        End Get    End Property    ''' <summary>    ''' Gets the quotation character wrapping every field.    ''' </summary>    ''' <value>The quotation character wrapping every field.</value>    Public ReadOnly Property Quote As Char        Get            Return _quote        End Get    End Property#End RegionEnd Class

using System;using System.Collections.Generic;using System.Text;using System.IO;namespace CsvIO.Csv{    /// <summary>    /// 快速写入数据到CSV文件    /// </summary>    public static class CsvWriter    {        #region Constants        /// <summary>        /// Defines the default delimiter character separating each field.        /// </summary>        public const char DefaultDelimiter = ',';        /// <summary>        /// Defines the default quote character wrapping every field.        /// </summary>        public const char DefaultQuote = '"';        /// <summary>        /// Defines the default escape character letting insert quotation characters inside a quoted field.        /// </summary>        public const char DefaultEscape = '"';        /// <summary>        /// The space character.        /// </summary>        private const char SPACE = ' ';        /// <summary>        /// The carriage return character. Escape code is <c>\r</c>.        /// </summary>        private const char CR = (char)0x0d;        /// <summary>        /// The line-feed character. Escape code is <c>\n</c>.        /// </summary>        private const char LF = (char)0x0a;        #endregion        #region Write        public static void Write(TextWriter writer, IEnumerable<string> row)        {            Write(writer, row, DefaultDelimiter);        }        public static void Write(TextWriter writer, IEnumerable<string> row, char delimiter)        {            bool start = false;            foreach (string str in row)            {                if (start == true)                    writer.Write(delimiter);                else                    start = true;                writer.Write(CsvString(str, delimiter));            }            writer.WriteLine();        }        private static string CsvString(string str, char delimiter)        {            if (string.IsNullOrEmpty(str)) return string.Empty;            bool delimit = false;            StringBuilder sb = new StringBuilder();            foreach (char c in str)            {                if (c == delimiter || c == CR || c == LF)                {                    delimit = true;                }                else if (c == DefaultQuote)                {                    sb.Append(DefaultQuote);                    delimit = true;                }                sb.Append(c);            }            if (delimit)            {                sb.Insert(0, DefaultEscape);                sb.Append(DefaultEscape);            }            return sb.ToString();        }        #endregion    }}