关于ColumnStyle的问题！(100分)

在ColumnStyle中的ENTITYCODE列无法显示出来，选择到的列竟然是ENTITYCODE列的内容？？！！！ 请各位帮忙，看问题在哪里？？？？
代码如下：
private void CreateStylesDetail ( DataGrid dg )
{
// Create a DataGridTableStyle for the customers table
DataGridTableStyle style = new DataGridTableStyle ( ) ;
// Map this style to the Customers DataTable
style.MappingName = "ENTITY_COLUMNLIST" ;
// Setup each alternate row in a different colour
style.AlternatingBackColor = System.Drawing.Color.Bisque ;



DataGridListBoxColumnStyle ENTITYCODE = new DataGridListBoxColumnStyle ( ) ;

ENTITYCODE.HeaderText = "实体代码" ;
ENTITYCODE.MappingName = "ENTITYCODE" ;
ENTITYCODE.Width = 100 ;

ENTITYCODE.DataSource = this.dsMaster.Tables["ENTITY_COLUMNLIST"];
ENTITYCODE.ValueMember = "ENTITYCODE";
ENTITYCODE.DisplayMember = "ENTITYCODE";



style.GridColumnStyles.AddRange ( new DataGridColumnStyle [] { ENTITYCODE, TABLECODE,COLUMNCODE ,COLUMNALIAS } ) ;



dg.TableStyles.Add ( style ) ;

}

请大家看看.