Question

I have a gridview that is bind to the datatable. how to programmaticaly change the color of the 1-st column, after the binding has been done?

Answer 1

You have to do it while binding is taking place in the RowDataBound Event.

Set the color of the cell in the 1st column in the event:

protected void gridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
    e.Row.Cells[0].BackColor = Color.Red
}