//in case if you want to show designation id in textbox
protected void grdview_SelectedIndexChanged(object sender, EventArgs e)
{
TextBox1.Text=grdview.SelectedRow.Cells[0].Text;
}
//in case if you want to show designation name in textbox
<pre lang="cs">protected void grdview_SelectedIndexChanged(object sender, EventArgs e)
{
TextBox1.Text=grdview.SelectedRow.Cells[1].Text;
}</pre>
make it answer and also rate if it satisfies you..