AspxGridView selection at runtime

I h开发者_如何学编程ave an aspxGridView on my page, and i create the columns at runtime. I also add CommandColumn with ShowSelectCheckBox set to true. But after i select one row and click a button to get the row values, AspxGridView.Selection.Count returns 0. I create this GridView on AspxButtons Click event also for paging, create the gridView on Page_Init. Here is the code to create the AspxGridView:

Colenter code hereorCollection colorCol = ConfAttributesManager.Instance
                                                               .GetColors();

if (colorCol.Count > 0)
{
    GridViewDataTextColumn grdColorCodeColumn = new GridViewDataTextColumn();
    grdColorCodeColumn.FieldName = "ColorCode";

    GridViewDataTextColumn grdDescriptionColumn = new GridViewDataTextColumn();
    grdDescriptionColumn.FieldName = "Description";

    gv_Attributes.Columns.Clear();
    gv_Attributes.Columns.Add(grdColorCodeColumn);
    gv_Attributes.Columns.Add(grdDescriptionColumn);
    GridViewCommandColumn grdCmdColumn = new GridViewCommandColumn();
    grdCmdColumn.ShowSelectCheckbox = true;
    grdCmdColumn.VisibleIndex = 0;
    gv_Attributes.Columns.Add(grdCmdColumn);

    gv_Attributes.DataSource = colorCol;
    gv_Attributes.DataBind();
 }

I don't know where do i make a mistake?

Thanks for your help.

It seems that you do not specify the ASPxGridView.KeyFieldName property that is required for Row Selection operation:

gv_Attributes.KeyFieldName = "ColorCode";
//gv_Attributes.KeyFieldName = Unique Key Field;