DataGrid的ColumnCaption怎么无法设置？

我从MSDN Help中抄了如下的代码，并使用。
但是结果并没有如帮助中描述的那样，Column Caption被设置为指定的值，是不是DataGrid中还有其他什么地方需要设置的？

private void DisplayDataTable( DataGrid myDataGrid )
{
DataTable dt;
DataColumn dc;

dt = new DataTable("Customers");

//CustomerID column
dc = dt.Columns.Add( "CustomerID", System.Type.GetType( "System.Int32" ) );
dc.Unique = true;

//CustomerName column
dc = dt.Columns.Add( "CustomerName", System.Type.GetType( "System.String" ) );
dc.Caption = "Name";

//CreditLimit
dc = dt.Columns.Add( "CreditLimit", System.Type.GetType( "System.Double" ) );
dc.DefaultValue = 0;
dc.Caption = "Limit";

dt.Rows.Add( new object[] {1, "Jonathan", 23.44} );
dt.Rows.Add( new object[] {2, "Bill", 56.87} );

myDataGrid.SetDataBinding( dt, "" );
}

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DataGridTableStyle ts1 = new DataGridTableStyle();
ts1.RowHeaderWidth = 15;
ts1.MappingName = SaleData.SALE_SUMMARY_TABLE;

DataGridColumnStyle ColPartName = new DataGridTextBoxColumn();
ColPartName.MappingName = SaleData.SALE_SUMMARY_PART_NAME_FIELD;
ColPartName.HeaderText = "配件名称";
ColPartName.NullText = "";
ts1.GridColumnStyles.Add(ColPartName);

dataGridSaleSummary.TableStyles.Add(ts1);

---------------------------------------------------------------

dc.Caption 改为 dc.ColumnName