protected void Button1_Click(object sender, EventArgs e)
    {
        String post, branch;

        if (Page.IsValid)
        {
            String password = Encrypt(TextBox_password.Text);
            String name;
            if (RadioButtonList1.SelectedValue == "Student")
            {
                name = Data_Access.Login(TextBox_ID.Text, password, 1, out post, out branch);
                if (name == "")
                {
                    Response.Write("ID not registered");
                }
                else if (name == "Invalid Password")
                {
                    Response.Write(name);
                }
                else
                {
                    Session["student_name"] = name;
                    Session["sap_id"]       = TextBox_ID.Text;
                    FormsAuthentication.RedirectFromLoginPage(name, false);
                    Response.Redirect("Home_Student/Leave_Apply.aspx");
                }
            }
            else
            {
                name = Data_Access.Login(TextBox_ID.Text, password, 0, out post, out branch);
                if (name == "")
                {
                    Response.Write("Employee ID not registered");
                }
                else if (name == "Invalid Password")
                {
                    Response.Write(name);
                }
                else
                {
                    Session["employee_name"] = name;
                    Session["emp_id"]        = TextBox_ID.Text;
                    Session["post"]          = post;
                    Session["branch"]        = branch;
                    FormsAuthentication.RedirectFromLoginPage(name, false);
                    if (Session["post"].ToString() == "gate_check")
                    {
                        Response.Redirect("Gate_Check.aspx");
                    }
                    else if (Session["post"].ToString() == "warden")
                    {
                        Response.Redirect("Hostel_Check_Leave.aspx");
                    }
                    else
                    {
                        Response.Redirect("Employee_Check_Leave.aspx");
                    }
                }
            }
        }
    }