I try to get help for my problem. but wpf experts not give me the solution.(All are so busy?).
I try and find the solution. i hope this code help who have the same problem in wpf datagrid.
if (columnCount == 4)
dataGrid1.Columns.DisplayIndex = 3;
dataGrid1.Columns.DisplayIndex = 0;
dataGrid1.Columns.DisplayIndex = 1;
dataGrid1.Columns.DisplayIndex = 2;
thank u very much.