一个自定义的C#数据库操作基础类 SqlHelper

{ 
    public class SQLHelper 
    { 
        private string strConn = null; 
        private SqlConnection Conn = null; 
        private SqlCommand Cmd = null; 
        private SqlDataReader Sqlsdr = null; 
        public SQLHelper() 
        { 
            //利用反射连接数据库 
            strConn = ConfigurationManager.ConnectionStrings["strConn"].ConnectionString; 
            //strConn = "data source=192.168.24.83;initial catalog=NewsSystem;user id=sa;password=123456"; 
            Conn = new SqlConnection(strConn); 
        }

    /// <summary> 
    /// 状态 
    /// </summary> 
    /// <returns>SqlConnection</returns> 
    private SqlConnection GetConn() 
    { 
        if (Conn.State == ConnectionState.Closed) 
        { 
            Conn.Open(); 
        } 
        return Conn; 
    } 

    /// <summary> 
    /// 执行不带参数的增删改操作 
    /// </summary> 
    /// <param name="CmdText">执行的SQL语句或存储过程</param> 
    /// <param name="CmdType">类型</param> 
    /// <returns>增删改的操作数</returns> 

    public int ExecuteNonQuery(string CmdText, CommandType CmdType) 
    { 
        //数据库连接语句 
        int res; 
        try 
        { 
            Cmd = new SqlCommand(CmdText, GetConn()); 
            Cmd.CommandType = CmdType; 
            res = Cmd.ExecuteNonQuery(); 

        } 
        catch (Exception ex) 
        { 

            throw ex; 
        } 
        finally 
        { 
            if (Conn.State == ConnectionState.Open) 
            { 
                Conn.Close(); 
            } 
        } 
        return res; 
    } 

    /// <summary> 
    /// 执行带参数的增删改操作 
    /// </summary> 
    /// <param name="CmdText">执行的SQL语句或存储过程</param> 
    /// <param name="Parameters">参数</param> 
    /// <param name="CmdType">类型（SQL语句或存储过程）</param> 
    /// <returns>增删改的操作数</returns> 
    public int ExecuteNonQuery(string CmdText, SqlParameter[] Parameters, CommandType CmdType) 
    { 
        int res; 
        try 
        { 
            Cmd.Parameters.AddRange(Parameters); 
            Cmd = new SqlCommand(CmdText, GetConn()); 
            Cmd.CommandType = CmdType; 
            res = Cmd.ExecuteNonQuery(); 
        } 
        catch (Exception ex) 
        { 

            throw ex; 
        } 
        finally 
        { 
            if (Conn.State == ConnectionState.Open) 
            { 
                Conn.Close(); 
            } 
        } 
        return res; 
    } 


    /// <summary> 
    /// 不带参数的查询 
    /// </summary> 
    /// <param name="CmdText">执行的SQL语句或存储过程</param> 
    /// <param name="CmdType">类型</param> 
    /// <returns>查询的数据</returns> 
    public DataTable ExecuteQuery(string CmdText, CommandType CmdType) 
    { 
        DataTable dt = new DataTable(); 

        using (Sqlsdr = Cmd.ExecuteReader(CommandBehavior.CloseConnection)) 
        { 
            Cmd = new SqlCommand(CmdText, GetConn()); 
            Cmd.CommandType = CmdType; 
            dt.Load(Sqlsdr); 
        } 
        return dt; 
    } 

    /// <summary> 
    /// 带参数的查询 
    /// </summary> 
    /// <param name="CmdText">SQL语句或存储过程</param> 
    /// <param name="Parameters">参数</param> 
    /// <param name="CmdType">类型</param> 
    /// <returns>查询的数据</returns> 
    public DataTable ExecuteQuery(string CmdText, SqlParameter[] Parameters, CommandType CmdType) 
    { 
        DataTable dt = new DataTable(); 

        using (Sqlsdr = Cmd.ExecuteReader(CommandBehavior.CloseConnection)) 
        { 
            Cmd = new SqlCommand(CmdText, GetConn()); 
            Cmd.CommandType = CmdType; 
            Cmd.Parameters.AddRange(Parameters); 
            dt.Load(Sqlsdr); 
        } 
        return dt; 
    } 
} 

}</pre>