Wiring up an eventhandler in VB.NET

[Lee]

Can anyone provide a working example of dynamically creating the "ItemClick" event handler for the RadMenuEventHandler. I just cannot get it to work. I am dynamically creating a RadMenu from a SQL data source, which works just fine, and then I am trying to create the "ItemClick" event handler. I can dynamically create a .NET control such as a button and wire the event handler with no issue but just cannot get the RadMenu to wire up. Here is my current code.

Code page: (aspx page follows)

Imports System.Web
Imports Telerik.Web.UI

Partial Class MARS3MainMenu

Inherits System.Web.UI.Page

     Dim security As New Security
     Dim sess As New GlobalProperties
     Dim da As New DataAccess

     Dim menuInfo As New DataTable
     Dim securityLoginRole As String = String.Empty

    Dim WithEvents marsMenu As New RadMenu

     Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

          If Not Page.IsPostBack Then

               Dim computerName As String = Environment.MachineName.ToString()

               ' =================================================================
               ' IMPORTANT
               ' In order for the System.Web.HttpContext.Current.User.Identity.Name.ToString()
               ' to pull the loggin name of the user the following needs to be changed on the
               ' IIS server running the website:
               ' Under Authentication 'Anonymous Authentication must be disabled and
               '              'Windows Authentication must be enabled.
               ' If this is not done, no user information will be returned.
               Dim userName As String
               userName = System.Web.HttpContext.Current.User.Identity.Name.ToString()
               ' =================================================================

               Dim userLength As Int32 = userName.Length
               Dim userIndexOf As Int32 = userName.IndexOf(Chr(92)) + 1

               userName = userName.Substring(userIndexOf, userLength - userIndexOf)

 

               Dim userInfo As New DataTable()

               userInfo = security.GetMARSUserInformation(userName)

               Dim userInformation As String = userInfo.Rows(0)("FullName")
              securityLoginRole = userInfo.Rows(0)("MARSGroupName")

               If String.IsNullOrEmpty(userInformation) Or String.IsNullOrEmpty(securityLoginRole) Then

                    Response.Redirect("MARS3LoginErrorPage.aspx")

               End If

               sess.UserLoggedIn = True
               sess.UserLogin = userName
               sess.UserName = userInfo.Rows(0)("FullName")
               sess.UserID = userInfo.Rows(0)("SalesID")
               sess.UserRole = securityLoginRole

               Master.MenuButtonVisible = False
               Master.LabelReportBeingRun = "Main Menu"

            ' sess.UserRole
               PopulateMenu()

          End If

     End Sub

     Private Sub PopulateMenu()

          AddHandler marsMenu.ItemClick, AddressOf marsMenu_ItemClick

          marsMenu.Flow = ItemFlow.Vertical
          menuInfo = da.BuildMenuInformation()

 

          For Each row As DataRow In menuInfo.Rows

               Dim hierarchyLevel As Int16 = Convert.ToInt16(row("HierarchyLevel"))
               Dim item As RadMenuItem

               Select Case hierarchyLevel

                    Case 1

                         If row(securityLoginRole) = "Y" Then

                              Dim level1 As RadMenuItem = New RadMenuItem(row("ItemName").ToString())
                              level1.Value = row("ItemID").ToString()
                              marsMenu.Items.Add(level1)

                         End If

                    Case 2

                         If row(securityLoginRole) = "Y" Then

                              Dim level2 As RadMenuItem = New RadMenuItem(row("ItemName").ToString())
                              level2.Value = row("ItemID").ToString()

                              item = marsMenu.FindItemByValue(row("ParentLevel").ToString())
                              item.Items.Add(level2)

                         End If

                    Case 3

                         If row(securityLoginRole) = "Y" Then

                              Dim level3 As RadMenuItem = New RadMenuItem(row("ItemName").ToString())
                              level3.Value = row("ItemID").ToString()

                              item = marsMenu.FindItemByValue(row("ParentLevel").ToString())
                              item.Items.Add(level3)

                         End If

               End Select

          Next

          Panel1.Controls.Add(marsMenu)

     End Sub

    Protected Sub marsMenu_ItemClick(ByVal sender As Object, ByVal e As RadMenuEventArgs) Handles marsMenu.ItemClick

          iFrame1.Attributes("src") = "SearchOptions.aspx"

     End Sub

End Class

ASPX Page:

<%@ Page Language="VB" MasterPageFile="~/MasterPageReports.master" AutoEventWireup="true"
    Inherits="MARS3_VBNET.MARS3MainMenu" Title="MARS Main Menu" CodeBehind="MARS3MainMenu.aspx.vb" %>

<%@ Register Src="CustomControls/ReportOptions.ascx" TagName="ReportOptions" TagPrefix="uc1" %>
<%@ Register Src="CustomControls/ReportSearchCriteria.ascx" TagName="ReportSearchCriteria"
    TagPrefix="uc2" %>
<%@ MasterType VirtualPath="~/MasterPageReports.master" %>
<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="Server">
    <style type="text/css">
        .style6
        {
            width: 203px;
        }
    </style>
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="Server">
    <asp:UpdatePanel ID="UpdatePanel1" runat="server">
        <ContentTemplate>
            <table cellpadding="3px">
                <tr>
                    <td>
                        <asp:Label ID="lblReportingOptions" runat="server" Text="Report Menu" Width="124px"
                            Font-Underline="true"></asp:Label>
                    </td>
                </tr>
                <tr>
                    <td valign="top">
                        <asp:Panel ID="Panel1" runat="server">
                        </asp:Panel>
                       
                    </td>
                    <td>
                        <asp:Label ID="Label2" runat="server" Text="Microage" Width="150" ForeColor="White" ></asp:Label>
                    </td>
                    <td>
                        <iframe id="iFrame1" width="755" height="490" runat="server" ></iframe>
                    </td>
                </tr>
                <tr>
                    <td>
                        <asp:Label ID="Label1" runat="server" Text="MicroAge" Visible="false"></asp:Label>
                    </td>
                </tr>
                <tr>
                    <td>
                        <asp:Button ID="Button1" runat="server" Text="Submit" CssClass="btnGradientRed" />
                    </td>
                </tr>
            </table>
        </ContentTemplate>
    </asp:UpdatePanel>
    <br />
</asp:Content>

[Veronica]

Hello Lee,

I've created a sample project with structure similar to yours. You can see the event ItemClick successfuly fired. The only thing I've changed is the DataTable and the way the menu is binded:

Private Function CreateTestTable() As DataTable

        AddHandler marsMenu.ItemClick, AddressOf marsMenu_ItemClick

        Dim table As New DataTable()
        table.Columns.Add("ID")
        table.Columns.Add("ParentID")
        table.Columns.Add("Text")
        table.Columns.Add("Tooltip")
        table.Rows.Add(New String() {"1", Nothing, "root 1", "root 1 tooltip"})
        table.Rows.Add(New String() {"2", Nothing, "root 2", "root 1 tooltip"})
        table.Rows.Add(New String() {"3", "1", "child 1.1", "child 1.1 tooltip"})
        table.Rows.Add(New String() {"4", "1", "child 1.2", "child 1.2 tooltip"})
        table.Rows.Add(New String() {"5", "1", "child 1.3", "child 1.3 tooltip"})
        table.Rows.Add(New String() {"6", "5", "child 1.3.1", "child 1.3.1 tooltip"})
        table.Rows.Add(New String() {"7", "5", "child 1.3.2", "child 1.3.2 tooltip"})
        table.Rows.Add(New String() {"8", "5", "child 1.3.3", "child 1.3.3 tooltip"})
        Return table
    End Function

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        If Not Page.IsPostBack Then
            marsMenu.DataSource = CreateTestTable()
            'Establish hierarchy:
            marsMenu.DataFieldID = "ID"
            marsMenu.DataFieldParentID = "ParentID"
            marsMenu.DataTextField = "Text"
            marsMenu.DataValueField = "ID"
            marsMenu.DataBind()
        End If

        Panel1.Controls.Add(marsMenu)
    End Sub

Please take a look at the attached project and let me know if this was helpful. 

Regards,
Veronica Milcheva
the Telerik team

[Lee]

Veronica,

Okay, I looked at your project and I had pretty much figured all this out.

Here is my question. Your building the Menu inside or the If statement

If Not Page.IsPostBack Then

But adding to the panel control on every postback.

How does viewstate of the Panel/menu control fit into all of this.

I changed my project to match yours - I put the building of the menu inside the if statement and then
put the Panel1.Controls.Add(marsMenu) outside the if statement and it no longer works.

I have everything working now, just not clear on why I have to rebuild the menu upon every post back.
I thought that was the purpose of viewstate. What am I missing?

Lee

[Veronica]

Hello Lee,

By default the whole Telerik control is not persisted in viewstate. There are only particular properties or items. That's why you need to add the control in the panel on each postback. However the binding could be done only once in the !IsPostBack conditional statement.

Greetings,
Veronica MIlcheva
the Telerik team