一个挺好用的数据库操作类

using System;
using System.Data;
using System.Configuration;
using System.Data.SqlClient;
using System.Collections;
using System.Collections.Specialized;
using System.Data.Common;
using System.Collections.Generic;
using System.IO;

namespace Lib
{
    public class SqlHelper
    {
       
   //数据库连接字符串(web.config来配置)，可以动态更改connectionString支持多数据库.  
       // public string path = Application.Info.DirectoryPath;
        public string connectionString = "Data Source=.\\SQLEXPRESS;AttachDbFilename=|DataDirectory|\\e5mhelpsystem.mdf;Integrated Security=True;User Instance=True";

#region 公用方法

  public   int GetMaxID(string FieldName,string TableName)
  {
   string strsql = "select max(" + FieldName + ") from " + TableName;
   object obj = GetSingle(strsql);
   if (obj == null)
   {
    return 1;
   }
   else
   {
    return int.Parse(obj.ToString());
   }
  }
  public  bool Exists(string strSql, params SqlParameter[] cmdParms)
  {
   object obj = GetSingle(strSql, cmdParms);
   int cmdresult;
   if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
   {
    cmdresult = 0;
   }
   else
   {
    cmdresult = int.Parse(obj.ToString());
   }
   if (cmdresult == 0)
   {
    return false;
   }
   else
   {
    return true;
   }
  }
  #endregion

  #region  执行简单SQL语句

  /// <summary>
  /// 执行SQL语句，返回影响的记录数
  /// </summary>
  /// <param name="SQLString">SQL语句</param>
  /// <returns>影响的记录数</returns>
  public   int ExecuteSql(string SQLString)
  {
   using (SqlConnection connection = new SqlConnection(connectionString))
   {    
    using (SqlCommand cmd = new SqlCommand(SQLString,connection))
    {
     try
     {  
      connection.Open();
      int rows=cmd.ExecuteNonQuery();

      return rows;
     }
     catch(System.Data.SqlClient.SqlException E)
     {

      throw new Exception(E.Message+"<br>"+SQLString);
     }
    }    
   }
  }
 

  /// <summary>
  /// 执行多条SQL语句，实现数据库事务。
  /// </summary>
  /// <param name="SQLStringList">多条SQL语句</param>  
  public   void ExecuteSqlTran(ArrayList SQLStringList)
  {
   using (SqlConnection conn = new SqlConnection(connectionString))
   {
    conn.Open();
    SqlCommand cmd = new SqlCommand();
    cmd.Connection=conn;    
    SqlTransaction tx=conn.BeginTransaction();   
    cmd.Transaction=tx;    
    try
    {     
     for(int n=0;n<SQLStringList.Count;n++)
     {
      string strsql=SQLStringList[n].ToString();
      if (strsql.Trim().Length>1)
      {
       cmd.CommandText=strsql;
       cmd.ExecuteNonQuery();
      }
     }          
     tx.Commit();     
    }
    catch(System.Data.SqlClient.SqlException E)
    {  
     tx.Rollback();
     throw new Exception(E.Message);
    }
   }
 
  }
  /// <summary>
  /// 执行带一个存储过程参数的的SQL语句。
  /// </summary>
  /// <param name="SQLString">SQL语句</param>
  /// <param name="content">参数内容,比如一个字段是格式复杂的文章，有特殊符号，可以通过这个方式添加</param>
  /// <returns>影响的记录数</returns>
  public   int ExecuteSql(string SQLString,string content)
  {    
   using (SqlConnection connection = new SqlConnection(connectionString))
   {
    SqlCommand cmd = new SqlCommand(SQLString,connection);  
    System.Data.SqlClient.SqlParameter  myParameter = new System.Data.SqlClient.SqlParameter ( "@content", SqlDbType.NText);
    myParameter.Value = content ;
    cmd.Parameters.Add(myParameter);
    try
    {
     connection.Open();
     int rows=cmd.ExecuteNonQuery();
     return rows;
    }
    catch(System.Data.SqlClient.SqlException E)
    {    
     throw new Exception(E.Message);
    }
    finally
    {
     cmd.Dispose();
                    connection.Close();
                    connection.Dispose();
    } 
   }

  }  
  /// <summary>
  /// 向数据库里插入图像格式的字段(和上面情况类似的另一种实例)
  /// </summary>
  /// <param name="strSQL">SQL语句</param>
  /// <param name="fs">图像字节,数据库的字段类型为image的情况</param>
  /// <returns>影响的记录数</returns>
  public   int ExecuteSqlInsertImg(string strSQL,byte[] fs)
  {  
   using (SqlConnection connection = new SqlConnection(connectionString))
   {
    SqlCommand cmd = new SqlCommand(strSQL,connection); 
    System.Data.SqlClient.SqlParameter  myParameter = new System.Data.SqlClient.SqlParameter ( "@fs", SqlDbType.Image);
    myParameter.Value = fs ;
    cmd.Parameters.Add(myParameter);
    try
    {
     connection.Open();
     int rows=cmd.ExecuteNonQuery();
     return rows;
    }
    catch(System.Data.SqlClient.SqlException E)
    {    
     throw new Exception(E.Message);
    }
    finally
    {
     cmd.Dispose();
                    connection.Close();
                    connection.Dispose();
    }    
   }

 
  }
  
  /// <summary>
  /// 执行一条计算查询结果语句，返回查询结果（object）。
  /// </summary>
  /// <param name="SQLString">计算查询结果语句</param>
  /// <returns>查询结果（object）</returns>
  public   object GetSingle(string SQLString)
  {
   using (SqlConnection connection = new SqlConnection(connectionString))
   {
    using(SqlCommand cmd = new SqlCommand(SQLString,connection))
    {
     try
     {
      connection.Open();
      object obj = cmd.ExecuteScalar();
      if((Object.Equals(obj,null))||(Object.Equals(obj,System.DBNull.Value)))
      {     
       return null;
      }
      else
      {
       return obj;
      }    
     }
     catch(System.Data.SqlClient.SqlException e)
     {      
      
      throw new Exception(e.Message);
     } 
    }

   }
 
  }
  /// <summary>
  /// 执行查询语句，返回SqlDataReader
  /// </summary>
  /// <param name="strSQL">查询语句</param>
  /// <returns>SqlDataReader</returns>
  public   SqlDataReader ExecuteReader(string strSQL)
  {
   SqlConnection connection = new SqlConnection(connectionString);   
   SqlCommand cmd = new SqlCommand(strSQL,connection);    
   try
   {
    connection.Open(); 
    SqlDataReader myReader = cmd.ExecuteReader();

    return myReader;
   }
   catch(System.Data.SqlClient.SqlException e)
   {

                throw new Exception(e.Message);
   }
   
   
  }

        /// <summary>
        /// 执行查询语句，返回结果第一行第一列的值
        /// </summary>
        /// <param name="strSQL"></param>
        /// <returns></returns>
        public string  Executestring(string strSQL)
        {
            SqlConnection connection = new SqlConnection(connectionString);
            SqlCommand cmd = new SqlCommand(strSQL, connection);
            string str ="";
            try
            {
                connection.Open();
                str = (string)cmd.ExecuteScalar();
 
                return str;
            }
            catch (System.Data.SqlClient.SqlException e)
            {
 
                throw new Exception(e.Message);
            }

        }
     

  /// <summary>
  /// 执行查询语句，返回DataSet
  /// </summary>
  /// <param name="SQLString">查询语句</param>
  /// <returns>DataSet</returns>
  public   DataSet Query(string SQLString)
  {
   using (SqlConnection connection = new SqlConnection(connectionString))
   {
    DataSet ds = new DataSet();
    try
    {
     connection.Open();
     SqlDataAdapter command = new SqlDataAdapter(SQLString,connection);

     command.Fill(ds,"ds");
    }
    catch(System.Data.SqlClient.SqlException ex)
    {
                   
                    throw new Exception(ex.Message);
    }
 
                return ds;
   }   
  }

        /// <summary>
        /// 执行查询语句，返回DataView
        /// </summary>
        /// <param name="SQLString">查询语句</param>
        /// <returns>DataView</returns>
        public  DataView QueryView(string SQLString)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                DataSet ds = new DataSet();
                try
                {
                    connection.Open();
                    SqlDataAdapter command = new SqlDataAdapter(SQLString, connection);

                    command.Fill(ds, "ds");

                }
                catch (System.Data.SqlClient.SqlException ex)
                {
                    throw new Exception(SQLString + "<br>" + ex.Message);
                }
                connection.Close();
                connection.Dispose();
                return ds.Tables[0].DefaultView;
            }
        }

        /// <summary>
        /// 执行查询语句，返回DataTable
        /// </summary>
        /// <param name="SQLString">查询语句</param>
        /// <returns>DataTable</returns>
        public   DataTable QueryTable(string SQLString)
        {
            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                DataSet ds = new DataSet();
                try
                {
                    connection.Open();
                    SqlDataAdapter command = new SqlDataAdapter(SQLString, connection);
                    command.Fill(ds, "ds");
                }
                catch (System.Data.SqlClient.SqlException ex)
                {
                    throw new Exception(ex.Message);
                }

                 return ds.Tables[0];
            }
        }

 

  #endregion

  #region 执行带参数的SQL语句

  /// <summary>
  /// 执行SQL语句，返回影响的记录数
  /// </summary>
  /// <param name="SQLString">SQL语句</param>
  /// <returns>影响的记录数</returns>
  public   int ExecuteSql(string SQLString,params SqlParameter[] cmdParms)
  {
   using (SqlConnection connection = new SqlConnection(connectionString))
   {    
    using (SqlCommand cmd = new SqlCommand())
    {
     try
     {  
      PrepareCommand(cmd, connection, null,SQLString, cmdParms);
      int rows=cmd.ExecuteNonQuery();
      cmd.Parameters.Clear();
      return rows;
     }
     catch(System.Data.SqlClient.SqlException E)
     {    
      throw new Exception(E.Message);
     }
 
    }    
   }
  }
  
   
  /// <summary>
  /// 执行多条SQL语句，实现数据库事务。
  /// </summary>
  /// <param name="SQLStringList">SQL语句的哈希表（key为sql语句，value是该语句的SqlParameter[]）</param>
  public   void ExecuteSqlTran(Hashtable SQLStringList)
  {   
   using (SqlConnection conn = new SqlConnection(connectionString))
   {
    conn.Open();
    using (SqlTransaction trans = conn.BeginTransaction())
    {
     SqlCommand cmd = new SqlCommand();
     try
     {
      //循环
      foreach (DictionaryEntry myDE in SQLStringList)
      { 
       string  cmdText=myDE.Key.ToString();
       SqlParameter[] cmdParms=(SqlParameter[])myDE.Value;
       PrepareCommand(cmd,conn,trans,cmdText, cmdParms);
       int val = cmd.ExecuteNonQuery();
       cmd.Parameters.Clear();

       trans.Commit();
      }     
     }
     catch
     {
      trans.Rollback();
      throw;
     }
    }    
   }
  }
 
    
  /// <summary>
  /// 执行一条计算查询结果语句，返回查询结果（object）。
  /// </summary>
  /// <param name="SQLString">计算查询结果语句</param>
  /// <returns>查询结果（object）</returns>
  public   object GetSingle(string SQLString,params SqlParameter[] cmdParms)
  {
   using (SqlConnection connection = new SqlConnection(connectionString))
   {
    using (SqlCommand cmd = new SqlCommand())
    {
     try
     {
      PrepareCommand(cmd, connection, null,SQLString, cmdParms);
      object obj = cmd.ExecuteScalar();
      cmd.Parameters.Clear();
      if((Object.Equals(obj,null))||(Object.Equals(obj,System.DBNull.Value)))
      {     
       return null;
      }
      else
      {
       return obj;
      }    
     }
     catch(System.Data.SqlClient.SqlException e)
     {    
      throw new Exception(e.Message);
     }     
    }
   }
  }
  
  /// <summary>
  /// 执行查询语句，返回SqlDataReader
  /// </summary>
  /// <param name="strSQL">查询语句</param>
  /// <returns>SqlDataReader</returns>
  public   SqlDataReader ExecuteReader(string SQLString,params SqlParameter[] cmdParms)
  {  
   SqlConnection connection = new SqlConnection(connectionString);
   SqlCommand cmd = new SqlCommand();    
   try
   {
    PrepareCommand(cmd, connection, null,SQLString, cmdParms);
    SqlDataReader myReader = cmd.ExecuteReader();
    cmd.Parameters.Clear();
    return myReader;
   }
   catch(System.Data.SqlClient.SqlException e)
   {        
    throw new Exception(e.Message);
   }     
   
  }  
  
  /// <summary>
  /// 执行查询语句，返回DataSet
  /// </summary>
  /// <param name="SQLString">查询语句</param>
  /// <returns>DataSet</returns>
  public   DataSet Query(string SQLString,params SqlParameter[] cmdParms)
  {
   using (SqlConnection connection = new SqlConnection(connectionString))
   {
    SqlCommand cmd = new SqlCommand();
    PrepareCommand(cmd, connection, null,SQLString, cmdParms);
    using( SqlDataAdapter da = new SqlDataAdapter(cmd) )
    {
     DataSet ds = new DataSet(); 
     try
     {            
      da.Fill(ds,"ds");
      cmd.Parameters.Clear();
     }
     catch(System.Data.SqlClient.SqlException ex)
     {    
      throw new Exception(ex.Message);
     }   
     return ds;
    }    
   }   
  }

  private   void PrepareCommand(SqlCommand cmd,SqlConnection conn,SqlTransaction trans, string cmdText, SqlParameter[] cmdParms)
  {
   if (conn.State != ConnectionState.Open)
    conn.Open();
   cmd.Connection = conn;
   cmd.CommandText = cmdText;
   if (trans != null)
    cmd.Transaction = trans;
   cmd.CommandType = CommandType.Text;//cmdType;
   if (cmdParms != null)
   {
    foreach (SqlParameter parm in cmdParms)
     cmd.Parameters.Add(parm);
   }
  }

  #endregion

  #region 存储过程操作

  /// <summary>
  /// 执行存储过程
  /// </summary>
  /// <param name="storedProcName">存储过程名</param>
  /// <param name="parameters">存储过程参数</param>
  /// <returns>SqlDataReader</returns>
  public   SqlDataReader RunProcedure(string storedProcName, IDataParameter[] parameters )
  {
   SqlConnection connection = new SqlConnection(connectionString);
   SqlDataReader returnReader;
   connection.Open();
   SqlCommand command = BuildQueryCommand( connection,storedProcName, parameters );
   command.CommandType = CommandType.StoredProcedure;
   returnReader = command.ExecuteReader();    
   return returnReader;   
  }
  
  
  /// <summary>
  /// 执行存储过程
  /// </summary>
  /// <param name="storedProcName">存储过程名</param>
  /// <param name="parameters">存储过程参数</param>
  /// <param name="tableName">DataSet结果中的表名</param>
  /// <returns>DataSet</returns>
  public   DataSet RunProcedure(string storedProcName, IDataParameter[] parameters, string tableName )
  {
   using (SqlConnection connection = new SqlConnection(connectionString))
   {
    DataSet dataSet = new DataSet();
    connection.Open();
    SqlDataAdapter sqlDA = new SqlDataAdapter();
    sqlDA.SelectCommand = BuildQueryCommand(connection, storedProcName, parameters );
    sqlDA.Fill( dataSet, tableName );
    connection.Close();
    return dataSet;

              
   }
  }

  
  /// <summary>
  /// 构建 SqlCommand 对象(用来返回一个结果集，而不是一个整数值)
  /// </summary>
  /// <param name="connection">数据库连接</param>
  /// <param name="storedProcName">存储过程名</param>
  /// <param name="parameters">存储过程参数</param>
  /// <returns>SqlCommand</returns>
  private   SqlCommand BuildQueryCommand(SqlConnection connection,string storedProcName, IDataParameter[] parameters)
  {   
   SqlCommand command = new SqlCommand( storedProcName, connection );
   command.CommandType = CommandType.StoredProcedure;
   foreach (SqlParameter parameter in parameters)
   {
    command.Parameters.Add( parameter );
   }
   return command;   
  }
  
  /// <summary>
  /// 执行存储过程，返回影响的行数  
  /// </summary>
  /// <param name="storedProcName">存储过程名</param>
  /// <param name="parameters">存储过程参数</param>
  /// <param name="rowsAffected">影响的行数</param>
  /// <returns></returns>
  public   int RunProcedure(string storedProcName, IDataParameter[] parameters, out int rowsAffected )
  {
   using (SqlConnection connection = new SqlConnection(connectionString))
   {
    int result;
    connection.Open();
    SqlCommand command = BuildIntCommand(connection,storedProcName, parameters );
    rowsAffected = command.ExecuteNonQuery();
    result = (int)command.Parameters["ReturnValue"].Value;
    //Connection.Close();
    return result;
   }
  }
  
  /// <summary>
  /// 创建 SqlCommand 对象实例(用来返回一个整数值) 
  /// </summary>
  /// <param name="storedProcName">存储过程名</param>
  /// <param name="parameters">存储过程参数</param>
  /// <returns>SqlCommand 对象实例</returns>
  private   SqlCommand BuildIntCommand(SqlConnection connection,string storedProcName, IDataParameter[] parameters)
  {
   SqlCommand command = BuildQueryCommand(connection,storedProcName, parameters );
   command.Parameters.Add( new SqlParameter ( "ReturnValue",
    SqlDbType.Int,4,ParameterDirection.ReturnValue,
    false,0,0,string.Empty,DataRowVersion.Default,null ));
   return command;
  }
  #endregion 

    }

}

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顺便问一句:博客园里写文章时，工具栏上没有插入代码这个工具吗？我咋没看见呢，不会是没有吧？

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