Hi
Try the below code .
protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e)
{
int rowIndex = Convert.ToInt32(e.CommandArgument);
foreach (GridViewRow row in GridView1.Rows)
{
row.BackColor = row.RowIndex.Equals(rowIndex) ?
System.Drawing.Color.Red :
System.Drawing.Color.White;
}
}