Solved

ClientId for a control in a user control

Posted on 2006-06-20

ASP.NET

1 solution

1,054 Views

Last Modified: 2008-01-16

I am working on a tree view control for a project that I am currently involved in. This tree view is made of three parts: TreeNode class, TreeNodeCollection class, and TreeView user control. The control has one line of HTML, a div container. When I call a function, I need it to run through the tree node collection recursively and generate the links and buttons necessary. Ok, well I've got the code generating all of the links and buttons, but the actually hiding of the nodes isn't happening because the javascript requires the id of the containing div. I am coding it to take the ClientId of the div as I create it, but it is only giving me the id that fed to the control, and not the one used when the page is generated. This is doing some screwy stuff, so if you want to give me some pointers elsewhere, I'ld definitely appreciate it.

I'm not going to post all of the code, just what I find to be the problem areas.

TreeView.ascx html
<%@ Control Language="vb" AutoEventWireup="false" Codebehind="TreeView.ascx.vb" Inherits="PeCON.TreeView" TargetSchema="http://schemas.microsoft.com/intellisense/ie5" %>
<div id="TreeViewContainer" runat="server" style="text-align: left"></div>

TreeView.ascx.vb
Public Sub BuildTreeView()
' call recursive method for displaying nodes

'TreeViewContainer is defined in the Windows Generated Code section but is not instantiated when we come across this code
If IsNothing(TreeViewContainer) Then
TreeViewContainer = New Web.UI.HtmlControls.HtmlGenericControl("div")
Me.Controls.Add(TreeViewContainer)
End If

DisplayNodes(_nodes, TreeViewContainer, 0)
End Sub

Private Sub DisplayNodes(ByVal Nodes As TreeNodeCollection, ByVal Container As Web.UI.Control, ByVal Level As Integer)
For i As Integer = 0 To Nodes.Count - 1
Dim hl As New Web.UI.WebControls.HyperLink
hl.Text = Nodes(i).Name
hl.NavigateUrl = Nodes(i).Url
Container.Controls.Add(hl)

Dim newLine As New Web.UI.WebControls.Literal
newLine.Text = "<BR>"
Container.Controls.Add(newLine)

If Nodes(i).HasChildren Then
Dim btn As New Web.UI.WebControls.Image
btn.ID = "btn" & i.ToString & "_" & Level.ToString
btn.ImageUrl = "..\images\plus.gif"
Container.Controls.Add(btn)

Dim newDiv As New Web.UI.HtmlControls.HtmlGenericControl("div")
newDiv.ID = "div" & i.ToString & "_" & Level.ToString
newDiv.Style.Add("text-align", "left")
newDiv.Style.Add("margin-left", CStr(Level * 0.2) & "in")
DisplayNodes(Nodes(i).Children, newDiv, Level + 1)
Container.Controls.Add(newDiv)

btn.Attributes.Add("onclick", "ToggleDisplay(this, " & newDiv.ClientID & ")")
End If
Next
End Sub

Generated output:
<div id="mainContent_divContent" align="center" class="ContentPane">
      <img class="ContainerTopLeft" src="images\cont-tl.gif">
      <img class="ContainerTopRight" src="images\cont-tr.gif">
      <img class="ContainerBottomLeft" src="images\cont-bl.gif">
      <img class="ContainerBottomRight" src="images\cont-br.gif">
      <div>
            <a href="Design/eater.aspx">Databases</a><BR>
            <img id="mainContent_TreeView_btn0_0" onclick="ToggleDisplay(this, div0_0)" src="images/plus.gif" alt="" border="0" />
            <div id="mainContent_TreeView_div0_0" style="text-align:left;margin-left:0in;">
                  <a href="Design/someplace.aspx">PeCON</a><BR>
                  <img id="mainContent_TreeView_btn0_1" onclick="ToggleDisplay(this, div0_1)" src="images/plus.gif" alt="" border="0" />
                  <div id="mainContent_TreeView_div0_1" style="text-align:left;margin-left:0.2in;">
                        <a href="Design/blah.aspx">Stored Procedures</a><BR>
                        <a href="Design/blah.aspx">Tables</a><BR>
                        <a href="Design/blah.aspx">Views</a><BR>
                        <a href="Design/blah.aspx">User Defined Functions</a><BR>
                  </div>
            </div>
      </div>
</div>

Comment

Question by:fizch

[X]

Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

Help others & share knowledge
Earn cash & points
Learn & ask questions

Join The Community

15 Comments

LVL 4

Expert Comment

by:gregg1ep00

ID: 169460182006-06-20

If you're instantiating the div from code, you need to set the "Id" property or else the tag will not get rendered with a client-side id. Simply add the line:

TreeViewContainer.Id = "TreeViewContainer"

to your BuildTreeView() method like this:

Public Sub BuildTreeView()
' call recursive method for displaying nodes

'TreeViewContainer is defined in the Windows Generated Code section but is not instantiated when we come across this code
If IsNothing(TreeViewContainer) Then
TreeViewContainer = New Web.UI.HtmlControls.HtmlGenericControl("div")
TreeViewContainer.Id = "TreeViewContainer"
Me.Controls.Add(TreeViewContainer)
End If

DisplayNodes(_nodes, TreeViewContainer, 0)
End Sub

LVL 6

Author Comment

by:fizch

ID: 169462412006-06-20

Ok, that got me one step closer, but I still do not have the entire ClientId for the divs that I am trying to pass to the javascript.

LVL 4

Expert Comment

by:gregg1ep00

ID: 169463622006-06-20

Ok, a few questions:
1) Which version of .NET are you using?
2) What page event are you launching your "BuildTreeView()" method from?

LVL 6

Author Comment

by:fizch

ID: 169463872006-06-20

1) I am using 1.1
2) Page_Load of the main page

LVL 4

Expert Comment

by:gregg1ep00

ID: 169465362006-06-20

Ok, try this...

Instead of using the <div id="TreeViewContainer"> in the html, can you try using an <asp:Panel> control? I think what's happening is, because HtmlGenericControl does not implement INamingContainer, it's not rendering the ClientID properly. Panel DOES, however, implement INamingContainer, so this may resolve your issue altogether. The Panel control, IIRC, renders itself as a div.

You can also safely get rid of these lines in the "BuildTreeView()" method:

If IsNothing(TreeViewContainer) Then
TreeViewContainer = New Web.UI.HtmlControls.HtmlGenericControl("div")
Me.Controls.Add(TreeViewContainer)
End If

You may also want to try replacing all your HtmlGenericControls in code (i.e., newDiv in DisplayNodes() ) with Panel controls.

LVL 6

Author Comment

by:fizch

ID: 169466672006-06-20

Ok, that didn't really help at all. I've got the same issue as before. The client id is still listing the information I fed it.

LVL 4

Expert Comment

by:gregg1ep00

ID: 169467002006-06-20

Wow, ok. I must be confusing myself now. Sorry about that. ;)

Can you give me an updated generated output?
Thx

LVL 6

Author Comment

by:fizch

ID: 169467982006-06-20

Ok, you will notice that the image and the hyperlink have switched places. I've done a little rearranging to get the information setup properly.

<div id="mainContent_divContent" align="center" class="ContentPane">
      <img class="ContainerTopLeft" src="images\cont-tl.gif">
      <img class="ContainerTopRight" src="images\cont-tr.gif">
      <img class="ContainerBottomLeft" src="images\cont-bl.gif">
      <img class="ContainerBottomRight" src="images\cont-br.gif">
      <div id="mainContent_TreeView_TreeViewContainer">
            <img id="mainContent_TreeView_btn0_0" onclick="ToggleDisplay(this, div0_0)" src="images/plus.gif" alt="" border="0" /> 
            <a href="design/eater.aspx">Databases</a><BR>
            <div id="mainContent_TreeView_div0_0" style="text-align:left;margin-left:0.1in;">
                  <img id="mainContent_TreeView_btn0_1" onclick="ToggleDisplay(this, div0_1)" src="images/plus.gif" alt="" border="0" /> 
                  <a href="design/someplace.aspx">PeCON</a><BR>
                  <div id="mainContent_TreeView_div0_1" style="text-align:left;margin-left:0.2in;">
                        <a href="design/blah.aspx">Stored Procedures</a><BR>
                        <a href="design/blah.aspx">Tables</a><BR>
                        <a href="design/blah.aspx">Views</a><BR>
                        <a href="design/blah.aspx">User Defined Functions</a><BR>
                  </div>
            </div>
      </div>
</div>

LVL 4

Expert Comment

by:gregg1ep00

ID: 169469312006-06-20

In your DisplayNodes() method, swap these two lines:

DisplayNodes(Nodes(i).Children, newDiv, Level + 1)
Container.Controls.Add(newDiv)

LVL 4

Expert Comment

by:gregg1ep00

ID: 169480172006-06-20

Clarification:

Swap these two lines:
DisplayNodes(Nodes(i).Children, newDiv, Level + 1)
Container.Controls.Add(newDiv)

So they read like this:
Container.Controls.Add(newDiv)
DisplayNodes(Nodes(i).Children, newDiv, Level + 1)

LVL 6

Author Comment

by:fizch

ID: 169513772006-06-21

Alright, I didn't have any luck with that either. However, don't worry about it now. This is not like me at all, but I downloaded microsoft's treeview and I have that working. It's got a lot more functionality than I would have ever put into mine. Sorry about wasting your time.

LVL 4

Expert Comment

by:gregg1ep00

ID: 169528562006-06-21

Well, here's what we know, which may explain why I thought my last suggestion would work...

Your DisplayNodes() method creates the controls necessary for the TreeView and generates the client-side "onclick" handler for your image control by using the ClientId property of the "newDiv" element. When you call into ClientId, it parses the control heirarchy and changes the Id attribute of the element, using all the Ids of that element's naming container heirarchy. So it's important to call ClientId only when you have the naming container heirarchy set up, or else you'll run into the problem you're having.

So basically, when you first call into DisplayNodes(), you're passing the TreeViewContainer as the Container parameter. When you get to the line where you set the client-side "onclick" handler and call newDiv.ClientId, the newDiv control must already be a member of the Container's control collection. Then you can recursively call back into DisplayNodes(), and in THAT instance of the method, the Container's control heirarchy will already be set up.

Regardless, I'm glad to know that you found a solution that works. Sorry we couldn't get it! Good luck! ;)

Cheers,
Greg

LVL 4

Expert Comment

by:gregg1ep00

ID: 169663622006-06-22

fizch seems to have gotten his solution to work and posted his solution (used Microsoft's TreeView control). Delete/Refund is fine with me. I'm glad he found a solution that worked for him.

Accepted Solution

by:RomMod

RomMod earned 0 total points

ID: 169986632006-06-27

Question closed - 500 points refunded.

Best regards,
RomMod
Experts Exchange
Community Support Moderator

Featured Post

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Some ASP.NET Practical tips

Article by: Easwaran

In an ASP.NET application, I faced some technical problems. In this article, I list them out and show the solutions that I found. I hope it will be useful. Problem: After closing a pop-up window, the parent page should be refreshed automaticall…

ASP.NET

Reduce the Page size Asp.Net

Article by: Kumaraswamy

Problem Hi all, While many today have fast Internet connection, there are many still who do not, or are connecting through devices with a slower connect, so light web pages and fast load times are still popular. If your ASP.NET page …

ASP.NET

How to monitor services on your network and why?

Video by: AdRem

Monitoring a network: how to monitor network services and why? Michael Kulchisky, MCSE, MCSA, MCP, VTSP, VSP, CCSP outlines the philosophy behind service monitoring and why a handshake validation is critical in network monitoring. Software utilized …