protected void BtnFind_Click(object sender, EventArgs e)
    {
        dt4 = obj.CheckPD(txtdate.Text, txttill.Text, Convert.ToInt32(ddnclass.SelectedValue), Convert.ToInt32(ddnsection.SelectedValue));
        gvdetails.DataSource = dt4;
        gvdetails.DataBind();


        dt5 = obj.CheckAD(txtdate.Text, txttill.Text, Convert.ToInt32(ddnclass.SelectedValue), Convert.ToInt32(ddnsection.SelectedValue));
        gvdetails1.DataSource = dt5;
        gvdetails1.DataBind();
    }