Dear CuongPuyol
i use also such type of code in my project i am placing example of my project events for you kindly check it if it is useful for you
private void gridSrch_DoubleClick(object sender, EventArgs e)
{
cmbitem.Text = gridSrch.Rows[gridSrch.CurrentRow.Index].Cells[0].Value.ToString();
panelSearch.Visible = false;
}
private void gridSrch_KeyDown(object sender, KeyEventArgs e)
{
cmbitem.Text = gridSrch.Rows[gridSrch.CurrentRow.Index].Cells[0].Value.ToString();
panelSearch.Visible = false;
}