天天学C#--数据访问类(一）

这是网上一位仁兄写的数据访问类，封装了大部分底层的数据库操作，比如返回DataSet，DataTable

执行SQL语句，存储过程等。它是支持SQLServer的，要改写成Oracle等其他数据库也很容易，用OleDb

控件即可.

MSDN真是好东东，要想编写通用的可移植的数据访问接口，可参考MSDN的这篇文章;

http://www.microsoft.com/china/MSDN/library/data/dataAccess/wriportap2.mspx

希望大家都能写出高质量的程序，做出高质量的软件,这是我们共同的目标.

using System;
using System.Data;
using System.Data.SqlClient;

namespace SysClassLibrary
{
 /// <summary>
 /// DataAccess 的摘要说明。
 /// <description>数据处理基类,调用方式：DataAccess.DataSet((string)sqlstr);或者DataAccess.DataSet((string)sqlstr,ref DataSet ds); </description>
 /// </summary>
 public class DataAccess
 {
  #region  属性
      protected static SqlConnection conn=new SqlConnection();
      protected static SqlCommand    comm=new SqlCommand();
  #endregion
  public DataAccess()
  {
       //init();
  }
  #region 内部函数  静态方法中不会执行DataAccess()构造函数

  /// <summary>
  /// 打开数据库连接
  /// </summary>
  private static void openConnection()
  {
   if (conn.State == ConnectionState.Closed)
   {
    //SysConfig.ConnectionString 为系统配置类中连接字符串，："server=localhost;database=databasename;uid=sa;pwd=;"

        conn.ConnectionString = SysConfig.ConnectionString ;
        comm.Connection =conn;
    try
    {
         conn.Open();
    }
    catch(Exception e)
    {
         throw new Exception(e.Message);
    }
   }
  }
  /// <summary>
  /// 关闭当前数据库连接
  /// </summary>
  private static void closeConnection()
  {
   if(conn.State == ConnectionState.Open)
        conn.Close();
   conn.Dispose();
   comm.Dispose();
  }
  #endregion
  /// <summary>
  /// 执行Sql查询语句
  /// </summary>
  /// <param name="sqlstr">传入的Sql语句</param>
  public static void ExecuteSql(string sqlstr)
  {
   try
   {
        openConnection();
        comm.CommandType =CommandType.Text ;
        comm.CommandText =sqlstr;
        comm.ExecuteNonQuery();
   }
   catch(Exception e)
   {
        throw new Exception(e.Message);
   }
   finally
   {
        closeConnection();
   }
  }

  /// <summary>
  /// 执行存储过程
  /// </summary>
  /// <param name="procName">存储过程名</param>
  /// <param name="coll">SqlParameters 集合</param>
  public static void ExecutePorcedure(string procName,SqlParameter[] coll)
  {
   try
   {
        openConnection();
        for(int i=0;i<coll.Length;i++)
        {
             comm.Parameters .Add(coll[i]);
        }
        comm.CommandType=CommandType.StoredProcedure ;
        comm.CommandText =procName;
        comm.ExecuteNonQuery();
   }
   catch(Exception e)
   {
        throw new Exception(e.Message);
   }
   finally
   {
        comm.Parameters.Clear();
        closeConnection();
   }
  }

  /// <summary>
  /// 执行存储过程并返回数据集
  /// </summary>
  /// <param name="procName">存储过程名称</param>
  /// <param name="coll">SqlParameter集合</param>
  /// <param name="ds">DataSet </param>
  public static void ExecutePorcedure(string procName,SqlParameter[] coll,ref DataSet ds)
  {
   try
   {
    SqlDataAdapter da=new SqlDataAdapter();
    openConnection();
    for(int i=0;i<coll.Length;i++)
    {
     comm.Parameters .Add(coll[i]);
    }
    comm.CommandType=CommandType.StoredProcedure ;
    comm.CommandText =procName;
   
    da.SelectCommand =comm;
    da.Fill(ds);
   }
   catch(Exception e)
   {
    throw new Exception(e.Message);
   }
   finally
   {
    comm.Parameters.Clear();
    closeConnection();
   }
  }

  /// <summary>
  /// 执行Sql查询语句并返回第一行的第一条记录,返回值为object 使用时需要拆箱操作 -> Unbox
  /// </summary>
  /// <param name="sqlstr">传入的Sql语句</param>
  /// <returns>object 返回值 </returns>
  public static object ExecuteScalar(string sqlstr)
  {
   object obj=new object();
   try
   {
    openConnection();
    comm.CommandType =CommandType.Text ;
    comm.CommandText =sqlstr;
    obj=comm.ExecuteScalar();
   }
   catch(Exception e)
   {
    throw new Exception(e.Message);
   }
   finally
   {
    closeConnection();
   }
   return obj;
  }

  /// <summary>
  /// 执行Sql查询语句,同时进行事务处理
  /// </summary>
  /// <param name="sqlstr">传入的Sql语句</param>
  public static void ExecuteSqlWithTransaction(string sqlstr)
  {
   SqlTransaction trans ;
   trans=conn.BeginTransaction();
   comm.Transaction =trans;
   try
   {
    openConnection();
    comm.CommandType =CommandType.Text ;
    comm.CommandText =sqlstr;
    comm.ExecuteNonQuery();
    trans.Commit();
   }
   catch
   {
    trans.Rollback();
   }
   finally
   {
    closeConnection();
   }
  }

  /// <summary>
  /// 返回指定Sql语句的SqlDataReader，请注意，在使用后请关闭本对象，同时将自动调用closeConnection()来关闭数据库连接
  /// 方法关闭数据库连接
  /// </summary>
  /// <param name="sqlstr">传入的Sql语句</param>
  /// <returns>SqlDataReader对象</returns>
  public static SqlDataReader dataReader(string sqlstr)
  {
   SqlDataReader dr=null;
   try
   {
    openConnection();
    comm.CommandText =sqlstr;
    comm.CommandType =CommandType.Text ;
    dr=comm.ExecuteReader(CommandBehavior.CloseConnection);
   }
   catch
   {
    try
    {
     dr.Close();
     closeConnection();
    }
    catch
    {
    }
   }
   return dr;
  }
  /// <summary>
  /// 返回指定Sql语句的SqlDataReader，请注意，在使用后请关闭本对象，同时将自动调用closeConnection()来关闭数据库连接
  /// 方法关闭数据库连接
  /// </summary>
  /// <param name="sqlstr">传入的Sql语句</param>
  /// <param name="dr">传入的ref DataReader 对象</param>
  public static void dataReader(string sqlstr,ref SqlDataReader dr)
  {
   try
   {
    openConnection();
    comm.CommandText =sqlstr;
    comm.CommandType =CommandType.Text ;
    dr=comm.ExecuteReader(CommandBehavior.CloseConnection);
   }
   catch
   {
    try
    {
     if(dr!=null && !dr.IsClosed)
      dr.Close();
    }
    catch
    {
    }
    finally
    {
     closeConnection();
    }
   }
  }

  /// <summary>
  /// 返回指定Sql语句的DataSet
  /// </summary>
  /// <param name="sqlstr">传入的Sql语句</param>
  /// <returns>DataSet</returns>
  public static DataSet dataSet(string sqlstr)
  {
   DataSet ds= new DataSet();
   SqlDataAdapter da=new SqlDataAdapter();
   try
   {
    openConnection();
    comm.CommandType =CommandType.Text ;
    comm.CommandText =sqlstr;
    da.SelectCommand =comm;
    da.Fill(ds);
   }
   catch(Exception e)
   {
    throw new Exception(e.Message);
   }
   finally
   {
    closeConnection();
   }
   return ds;
  }

  /// <summary>
  /// 返回指定Sql语句的DataSet
  /// </summary>
  /// <param name="sqlstr">传入的Sql语句</param>
  /// <param name="ds">传入的引用DataSet对象</param>
  public static void dataSet(string sqlstr,ref DataSet ds)
  {
   SqlDataAdapter da=new SqlDataAdapter();
   try
   {
    openConnection();
    comm.CommandType =CommandType.Text ;
    comm.CommandText =sqlstr;
    da.SelectCommand =comm;
    da.Fill(ds);
   }
   catch(Exception e)
   {
    throw new Exception(e.Message);
   }
   finally
   {
    closeConnection();
   }
  }
  /// <summary>
  /// 返回指定Sql语句的DataTable
  /// </summary>
  /// <param name="sqlstr">传入的Sql语句</param>
  /// <returns>DataTable</returns>
  public static DataTable dataTable(string sqlstr)
  {
   SqlDataAdapter da=new SqlDataAdapter();
   DataTable datatable=new DataTable();
   try
   {
    openConnection();
    comm.CommandType =CommandType.Text ;
    comm.CommandText =sqlstr;
    da.SelectCommand =comm;
    da.Fill(datatable);
   }
   catch(Exception e)
   {
    throw new Exception(e.Message);
   }
   finally
   {
    closeConnection();
   }
   return datatable;
  }

  /// <summary>
  /// 执行指定Sql语句,同时给传入DataTable进行赋值
  /// </summary>
  /// <param name="sqlstr">传入的Sql语句</param>
  /// <param name="dt">ref DataTable dt </param>
  public static void dataTable(string sqlstr,ref DataTable dt)
  {
   SqlDataAdapter da=new SqlDataAdapter();
   try
   {
    openConnection();
    comm.CommandType =CommandType.Text ;
    comm.CommandText =sqlstr;
    da.SelectCommand =comm;
    da.Fill(dt);
   }
   catch(Exception e)
   {
    throw new Exception(e.Message);
   }
   finally
   {
    closeConnection();
   }
  }
  /// <summary>
  /// 执行带参数存储过程并返回数据集合
  /// </summary>
  /// <param name="procName">存储过程名称</param>
  /// <param name="parameters">SqlParameterCollection 输入参数</param>
  /// <returns></returns>
  public static DataTable dataTable(string procName,SqlParameterCollection parameters)
  {
   SqlDataAdapter da=new SqlDataAdapter();
   DataTable datatable=new DataTable();
   try
   {
    openConnection();
    comm.Parameters.Clear();
    comm.CommandType=CommandType.StoredProcedure ;
    comm.CommandText =procName;
    foreach(SqlParameter para in parameters)
    {
     SqlParameter p=(SqlParameter)para;
     comm.Parameters.Add(p);
    }
    da.SelectCommand =comm;
    da.Fill(datatable);
   }
   catch(Exception e)
   {
    throw new Exception(e.Message);
   }
   finally
   {
    closeConnection();
   }
   return datatable;
  }

  public static DataView dataView(string sqlstr)
  {
   SqlDataAdapter da=new SqlDataAdapter();
   DataView dv=new DataView();
   DataSet ds=new DataSet();
   try
   {
    openConnection();
    comm.CommandType=CommandType.Text;
    comm.CommandText =sqlstr;
    da.SelectCommand =comm;
    da.Fill(ds);
    dv=ds.Tables[0].DefaultView;
   }
   catch(Exception e)
   {
    throw new Exception(e.Message);
   }
   finally
   {
    closeConnection();
   }
   return dv;
  }
 }

}