DBClass.cs 文件中：  adapt.Fill(ds,TableName); ds返回NULL，请解决下。
 

 /// <summary>
    /// 说  明：  返回数据集的表的集合
    /// 返回值：  数据源的数据表
    /// 参  数：  myCmd 执行SQL语句命令的SqlCommand对象，TableName 数据表名称
    /// </summary>
    public DataTable GetDataSet(SqlCommand myCmd, string TableName)
    {
        SqlDataAdapter adapt;
        DataSet ds = new DataSet();
        try
        {
            if (myCmd.Connection.State != ConnectionState.Open)
            {
                myCmd.Connection.Open();
            }
            adapt = new SqlDataAdapter(myCmd);
            adapt.Fill(ds,TableName);
            return ds.Tables[TableName];

        }
        catch (Exception ex)
        {
            throw new Exception(ex.Message, ex);

        }
        finally
        {
            if (myCmd.Connection.State == ConnectionState.Open)
            {
                myCmd.Connection.Close();

            }
        }

    }