private void userManagementToolStripMenuItem_Click(object sender, EventArgs e)
{
frmUserInfo frm = new frmUserInfo();
frm.MdiParent = this;
frm.Show();
}
private void dtgvStudent_CellDoubleClick(object sender, DataGridViewCellEventArgs e)
{
string mathe = dtgvStudent.CurrentRow.Cells[0].Value.ToString();
frmUserInfo frmUserInfo = new frmUserInfo(mathe);
frmUserInfo.Show(this);
}