数据库连接的多种方式（二）

/// <summary>
    /// 执行查询语句，返回DataSet
    /// </summary>
    /// <param name="SQLString">查询语句</param>
    /// <returns>DataSet</returns>
    public static DataSet Query(string SQLString, params SqlParameter[] cmdParms)
    {
        conn = new SqlConnection(connectionString);
        SqlCommand cmd = new SqlCommand();
        PrepareCommand(cmd, conn, 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 static 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 static SqlDataReader RunProcedure(string storedProcName, IDataParameter[] parameters)
    {
        conn = new SqlConnection(connectionString);
        SqlDataReader returnReader;
        conn.Open();
        SqlCommand command = BuildQueryCommand(conn, 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 static DataSet RunProcedure(string storedProcName, IDataParameter[] parameters, string tableName)
    {
        conn = new SqlConnection(connectionString);
        {
            DataSet dataSet = new DataSet();
            conn.Open();
            SqlDataAdapter sqlDA = new SqlDataAdapter();
            sqlDA.SelectCommand = BuildQueryCommand(conn, storedProcName, parameters);
            sqlDA.Fill(dataSet, tableName);
            conn.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 static SqlCommand BuildQueryCommand(SqlConnection conn, string storedProcName, IDataParameter[] parameters)
    {
        SqlCommand command = new SqlCommand(storedProcName, conn);
        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 static int RunProcedure(string storedProcName, IDataParameter[] parameters, out int rowsAffected)
    {
        conn = new SqlConnection(connectionString);
        int result;
        conn.Open();
        SqlCommand command = BuildIntCommand(conn, storedProcName, parameters);
        rowsAffected = command.ExecuteNonQuery();
        result = (int)command.Parameters["ReturnValue"].Value;
        conn.Close();
        return result;
    }
    private static SqlCommand BuildIntCommand(SqlConnection conn, string storedProcName, IDataParameter[] parameters)
    {
        SqlCommand command = BuildQueryCommand(conn, storedProcName, parameters);
        command.Parameters.Add(new SqlParameter("ReturnValue",
            SqlDbType.Int, 4, ParameterDirection.ReturnValue,
            false, 0, 0, string.Empty, DataRowVersion.Default, null));
        return command;
    }
    #endregion

}