<asp:LoginView
    ID="HeadLoginView" ...
    <AnonymousTemplate>
        <asp:Login ID="LoginUser" OnLoggedIn="LoginUser_LoggedIn" ... >
            <LayoutTemplate>
                <asp:Label ID="UserNameLabel" runat="server" AssociatedControlID="UserName">Username:</asp:Label>
                <asp:TextBox ID="UserName" runat="server" CssClass="textEntry"></asp:TextBox>
                <asp:Label ID="PasswordLabel" runat="server" AssociatedControlID="Password">Password:</asp:Label>
                <asp:TextBox ID="Password" runat="server" CssClass="passwordEntry" TextMode="Password"></asp:TextBox>
                <asp:CheckBox ID="RememberMe" runat="server"/>
                <asp:Label ID="RememberMeLabel" runat="server" AssociatedControlID="RememberMe" CssClass="inline">Remember me.</asp:Label>
                <asp:Button ID="LoginButton" runat="server" CommandName="Login" Text="Login" style="width:100%; height:35px"/>
            </LayoutTemplate>
        </asp:Login>
    </AnonymousTemplate>
    ...
</asp:LoginView>

protected void LoginUser_LoggedIn(object sender, EventArgs e)
{
    MembershipUser user = Membership.GetUser();
    if (Roles.IsUserInRole(user.UserName, "User"))
    {
        // Do something and redirect to user page...
    }

    if (Roles.IsUserInRole(user.UserName, "Admin"))
    {
        // Do something and redirect to admin page...
    }
}

string role = system.CheckAdminLogin(txtUserName.Text, txtPassword.Text);
    if (role == Role.admin.ToString() || role == Role.manager.ToString())
    {
        Users _user = _users.GetUserByUserName(txtUserName.Text);
        if (_user.Mode)
        {
            FormsAuthentication.SetAuthCookie(role, false);
            Session.Add("UserName", txtUserName.Text);
            Session.Add("UserID", _user.ID);
            Response.Redirect("System/ShowActivities.aspx");
        }
        else
        {
            lblLoginFail.Text = "your account is not authorized!";
            lblLoginFail.Visible = true;
        }
    }
    else
    {
        if (txtPassword.Text != "" && txtUserName.Text != "")
        {
            lblLoginFail.Text = Application["Wrong_login_data"].ToString();
            lblLoginFail.Visible = true;
        }
    }

protected void LoginUser_LoggedIn(object sender, EventArgs e)
{
    string userName = (LoginUser.FindControl(“UserName”) as TextBox).Text;
    //// or use
    ////  string userName = (e.Item.FindControl("UserName") as TextBox).Text;
    MembershipUser user = Membership.GetUser(userName);

    if (Roles.IsUserInRole(user.UserName, "User"))
    {
        // Do something and redirect to user page...
    }

    if (Roles.IsUserInRole(user.UserName, "Admin"))
    {
        // Do something and redirect to admin page...
    }
}

protected void LoginUser_LoggedIn(object sender, EventArgs e)
{
    String username = (HeadLoginView.FindControl("LoginUser") as Login).UserName;

    if (Roles.IsUserInRole(username, "User"))
    {
        //...
    }
    // ...
}