I have form.aspx in that there is dropdown

There is mutlilpe values in that drodown ..

e.g. Car Truck Bike Drink Factory

There is login page Login.aspx Login code

<asp:Label ID="Label3" runat="server" Text="Select values"></asp:Label>
<asp:DropDownList ID="regiondrop" runat="server" AutoPostBack="True" OnSelectedIndexChanged="regiondrop_SelectedIndexChanged">
</asp:DropDownList>
<asp:RequiredFieldValidator ControlToValidate="regiondrop" ID="RequiredFieldValidator1"
    runat="server" ErrorMessage="Select Region">
</asp:RequiredFieldValidator>

protected void Button1_Click(object sender, EventArgs e)
{
    try
    {
        //Label1.BackColor = "F8D8D7";
        loginmethod(txt_us.Text, txt_pwd.Text);

        Response.Redirect("WebForm1.aspx");
    }
    catch (Exception)
    {
        Label1.Text = ("Incorrect UserName/Password");
        Label1.Visible = true;
    }
    txt_us.Text = "";
    txt_pwd.Text = "";


}
public bool loginmethod(string UserName, string Password)
{
    TrackDataEntities1 td = new TrackDataEntities1();

    splogin1_Result sp = td.splogin1(UserName, Password).FirstOrDefault();
    if (sp.Password == txt_pwd.Text)
    {
        return true;
    }
    else
    {
        return false;
    }
}

Now there is two users .. admin and user . Now i want when admin login then with their id and password then he see some values from this list and when user login then he will see some values from this list for example when admin login then he may able to see only Factory value and when user login then he able to see all values except factory

how i do this ?