private void dgvMaterial_CellContentClick(object sender, DataGridViewCellEventArgs e)
{
for (int i = ; i < dgvMaterial.Rows.Count; i++)
{
DataGridViewCheckBoxCell ck = dgvMaterial.Rows[i].Cells[] as DataGridViewCheckBoxCell;
if (i != e.RowIndex)
{
ck.Value = false;
}
else
{
ck.Value = true;
}
}
}