Hello all - my first post here...

 I have a custom Navigation User Control which contains a TreeView inside of it.  I have placed this UserControl on my MasterPage.  All of my other pages will base their design on this Master Page - so the Navigation should show on each page.  The Navigation's TreeView points to a web.sitemap file. 

Everything works except that I cannot access the OnSelectedNodeChanged Event. 

Inside my userControl I have set the following attributes:

OnSelectedNodeChanged="OnClick"

I have also created a public OnClick event, and tried placing it in various locations - but none of them seem to work. 

I tried putting the Public OnClick event in the UserControl.ascx.cs file,

Also tried putting it in the MasterPage's code file -  MasterPage.cs,

None of these work - the SelectedNodeChanged event doesn't seem to get handled.

 Is this because the TreeView is nested inside a user control?

I need to handle this SelectedNodeChanged event.

Thanks

Hi Guitar Guy,

It sounds like you are doing the right things.  You've made the event handler public, not protected.  And you've assigned OnAdaptedSelectedNodeChanged rather than simply OnSelectedNodeChanged.  Putting the handler in the user control's code behind (usercontrol.acsx.cs) is the right thing.  I would have expected that to work.  Since it didn't we need to dig a bit deeper.

Are you willing to help with the debugging?  If so, here's what I recommend you do.

Use Visual Studio or VWD to run your web site in debug mode.  That means opening your web site in VWD or VS and hitting F5.  Put a break point at the first executable line within the method called RaisePostBackEvent in TreeViewAdapter.cs (or vb, depending on what language you've chosen to use).  Now try clicking on one of the tree nodes to cause the page to postback.  Do you break in RaisePostBackEvent?  If so, start walking through the execution of the code by hitting F10 again and again (slowly) and watching the logic flow.  Notice that RaisePostBackEvent has a call to Extender.RaiseAdaptedEvent for the SelectedNodeChanged event.  I'm guessing you are not going to reach that call because you said that your event handler doesn't get hit. However, it may be that you are actually hitting the call to Extender.RaiseAdaptedEvent.  If so, then you need to step INTO it by pressing F11 when you reach that line.

I took a look at the code for RaiseAdaptedEvent and it does look like there may be a problem in there in cases where the tree is in a user control rather than a page.  You'll see what I mean if you look at that method.  It looks at the tree's immediate parent and then it looks at the page to see if it can find the event handler function.  You're situation may be one where neither heuristic is good enough.  If that's the case, let me know and we'll work together to see if there is a simple way to enhance RaiseAdaptedEvent so it works properly in your case, too.

I look foward to hearing back from you.  Good luck.  We'll figure this out.

Hi Russ,

 Thanks for your reponse.  I realized that I made a typo in my code!  So in fact, I can set an OnClick event both in the code file for my user control AND my code behind file for my aspx page and both will get called.  Sorry about that and thanks for your help.

Thanks Russ for the tip. I had the similar problem. The selected nodechanged event is not raised if TreeView is in an updatepanel (using it with Ajax RC) and both of them are in the user control. So

For TreeView, 

.Parent is the System.Web.UI.Control

.Parent.Parnet is the updatepanel

.Parent.Parent.Parent is the user control, where the method lies.

WIth this, the following code in the RaiseAdaptedEvent method fails to invoke the SelectedNodeChanged event.

Thanks for the feedback, Harpreet.  I agree.  I think there's a flaw in the code I wrote originally for RaiseAdaptedEvent.  What do you think about something that walks up the parent-list looking for the event delegate method like this?

        public void RaiseAdaptedEvent(string eventName, EventArgs e)
        {
            string attr = "OnAdapted" + eventName;
            if ((AdaptedControl != null) && (!String.IsNullOrEmpty(AdaptedControl.Attributes[attr])))
            {
                string delegateName = AdaptedControl.Attributes[attr];
                MethodInfo method = null;
                Control methodOwner = AdaptedControl.Parent;
                while ((method == null) && (methodOwner != null))
                {
                    method = methodOwner.GetType().GetMethod(delegateName);
                    methodOwner = methodOwner.Parent;
                }
                if (method == null)
                {
                    methodOwner = AdaptedControl.Page;
                    method = methodOwner.GetType().GetMethod(delegateName);
                }
               
                if (method != null)
                {
                    object[] args = new object[2];
                    args[0] = AdaptedControl;
                    args[1] = e;
                    method.Invoke(methodOwner, args);
                }
            }
        }

I've not yet tested this but it seems like it would a pretty save/simple change to the code that would work in more case.  If you happen to try this (or if any readers happen to try this) please post the results: did it work to fix cases where events weren't being fired properly for adapted controls within user controls?

Couple of things, I think there is bug in the code; In the while loop

                while ((method == null) && (methodOwner != null))
                {
                    method = methodOwner.GetType().GetMethod(delegateName);
                    methodOwner = methodOwner.Parent;
                }

if method has been found, mothodowner should not be changed as it is needed to invoke the event. so it should be

                while ((method == null) && (methodOwner != null))
                {
                    method = methodOwner.GetType().GetMethod(delegateName);

                    if(method != null)

                      methodOwner = methodOwner.Parent;
                }

In addition to this, you dont need

                if (method == null)
                {
                    methodOwner = AdaptedControl.Page;
                    method = methodOwner.GetType().GetMethod(delegateName);
                }
as, while going through all the partents, you will reach to the Page ultimately, i.e evantually, methodowner.parent will be equal to Page.

Here is what I have used in my code. I have tested it for my needs and it is working fine. Please let me know there is still a bug for some other scnario that i have not been tested against.

Russ, on a different subject, I have also found additional bugs, one of them is described at setting ShowCheckBox = true & node hyperlink disappears??  and other is with the css, In my tree view, I have added a background color to the selected nodes in the css by setting

in the TreeViewExample css, the problem I am having is that , if the selected node has some childrens then the same background is also applied to all the children in the selected node ??? , ( used on IE 7). Any help ??

Oops, I forgot to put the modifed code that I am using, it is

Hi there!

I'm also having trouble with the TreeView adapter however looking at the recursion method above I have modified this loop into the following (appologies - this is in VB because I'm currently being forced to target DotNetNuke at gunpoint)

 I removed the exception to ensure that a missing handler does not throw an exception - this allows code to be commented out for debugging without the adapter code getting upset!

Just to clarify:

In the WebControlAdapterExtender.vb file, there is an error affecting treeview (using css adapters) when placed in user control.

The problem is that the SelectedNodeChanged event will not fire, as the extender will be looking for the event on the page and not in the user control.

Therefore, if the method is not firing, change this:

        Public Sub RaiseAdaptedEvent(ByVal eventName As String, ByVal e As EventArgs)
            Dim attr As String = "OnAdapted" + eventName
            If ((Not IsNothing(AdaptedControl)) AndAlso _
                (Not String.IsNullOrEmpty(AdaptedControl.Attributes(attr)))) Then
                Dim delegateName As String = AdaptedControl.Attributes(attr)
                Dim methodOwner As Control = AdaptedControl.Parent
                Dim method As MethodInfo = methodOwner.GetType().GetMethod(delegateName)
                If (IsNothing(method)) Then
                    methodOwner = AdaptedControl.Page
                    method = methodOwner.GetType().GetMethod(delegateName)
                End If
                If (Not IsNothing(method)) Then
                    Dim args() As Object = New Object(1) {}
                    args(0) = AdaptedControl
                    args(1) = e
                    method.Invoke(methodOwner, args)
                End If
            End If
        End Sub

        Public Sub RaiseAdaptedEvent(ByVal eventName As String, ByVal e As EventArgs)
            Dim attr As String = "OnAdapted" + eventName
            If ((Not IsNothing(AdaptedControl)) AndAlso _
                (Not String.IsNullOrEmpty(AdaptedControl.Attributes(attr)))) Then                
                Dim delegateName As String = AdaptedControl.Attributes(attr)
                Dim methodOwner As Control = AdaptedControl.Parent
                Dim method As MethodInfo = methodOwner.GetType().GetMethod(delegateName)
                While IsNothing(method)
                    method = methodOwner.GetType().GetMethod(delegateName)
                    If IsNothing(method) Then
                        methodOwner = methodOwner.Parent
                        If IsNothing(methodOwner) Then
                            Throw New Exception("Error! in control adapters!")
                        End If
                    End If
                End While

                If (Not IsNothing(method)) Then
                    Dim args() As Object = New Object(1) {}
                    args(0) = AdaptedControl
                    args(1) = e
                    method.Invoke(methodOwner, args)
                End If
            End If
        End Sub

I'm using a Control that derives from TreeView, so the RaiseAdaptedEvent actual need to start its search for the event handler in the current control, not the parent control.

A complete version of the modified C# therefore looks like this:

public void RaiseAdaptedEvent(string eventName, EventArgs e)
{
    string attr = "OnAdapted" + eventName;
    if ((AdaptedControl != null) && (!String.IsNullOrEmpty(AdaptedControl.Attributes[attr])))
    {
        string delegateName = AdaptedControl.Attributes[attr];
        Control methodOwner = AdaptedControl;
        MethodInfo method = null;               

        while (method == null)
        {
            method = methodOwner.GetType().GetMethod(delegateName);
            if (method == null)
            {
                methodOwner = methodOwner.Parent;
                if (methodOwner == null)
                {
                    throw new Exception("Error! in control adapters!");
                }
            }
        }

        if (method != null)
        {
            object[] args = new object[2];
            args[0] = AdaptedControl;
            args[1] = e;
            method.Invoke(methodOwner, args);
        }
    }
}