private void chk_CheckAll_CheckedChanged(object sender, EventArgs e)
{
if (chk_CheckAll.Checked == true)
{
foreach (DataGridViewRow row in dgv_Question.Rows)
{
row.Cells["Check"].Value = true;
}
}
else
{
foreach (DataGridViewRow row in dgv_Question.Rows)
{
row.Cells["Check"].Value = null;
}
}
}