I have a problem with expanding/collapsing a Treeview control in an Updatepanel which causes weird behavior and functions fine if placed outside the Updatepanel.
I have found that TreeViews is not supported in updatePanels so my question is:
What is a workaround to avoid a full postback whilst keeping expand/collapse functionality as well as TreeNode_clicks that updates another control?
Also why does it seem that some people use a TreeView inside an Updatepanel with success? Is this only an ASP2 prolbem?
It's the loading of the treeview javascript that fails under an updatepanel. I've tried putting some explanations and options below in bullet points.
The control will work in an updatepanel if it is visible straight away.
The control will not work in an updatepanel if it is made visible after a postback.
If you disable the client side javascript, the control will work in an updatepanel but will cause a postback every time a plus/minus is clicked.
Hope that helps
TreeView in .Net 2.0 doesn't need to postback on expand/collapse.
Have you tried to put an UpdatePanel around the control you wish to update with a trigger
< asp:PostBackTrigger ControlID="treeView" />
As declared by Microsoft, treeview is not compatible with UpdatePanel. So you are having all the issues. I have managed the same to a quite acceptable level in one of my project. You can refer to the posts on the same as follows: http://www.geekays.net/post/Using-TreeView-inside-AJAX-UpdatePanel.aspx and http://www.geekays.net/post/TreeView-control-postbacks-on-check-and-uncheck-of-the-nodes-Checkbox.aspx
Let me know if it helps.
Related
I'm using UpdatePanels in ContentPages sucefully, but now i'm trying to use one UpdatePanel in a MasterPage with an timer (i've setted the UpdateMode to conditional because the Timer) and i'm getting an problem: the update is refreshing the entire page (not like Ajax used in ContenPages).
It's because i'm using the UpdatePanel in the MasterPage?
Make sure the Timer sits within the UpdatePanel and not outside it or surround the Timer with another UpdatePanel. Also, you should check out the link medusa posted which covers some important points.
Are you setting up any triggers to point to the timer? Or where is the timer in relation to the update panel?
I have a control which has an ImageButton which is tied to an OnClick event... Upon clicking this control, a postback is performed and the event handler is not called. AutoEventWireup is set to true, and I've double checked spelling etc.... We haven't touched this control in over a year and it has been working fine until a couple of weeks ago.
We have made changes to controls which load this control... so I'm wondering, what kind of changes could we have made to stop this event handler from being called? There is quite a bit of Javascript going on, so this could be the culprit too...
Edit: Some clarification... we are dynamically loading the parent control of the ImageButton in the OnLoad event of the page... if that makes sense.
AutoEventWireup is irrelevant. Is your ImageButton loaded dynamically, i.e. not written out in mark up? If it is loaded onto the page late in the Page lifecycle e.g. in PreRender then the event will not fire.
If there is a JavaScript issue your page will not even PostBack. Is that happening?
Did you give the ImageButton an ID?
I def agree with what BritishDeveloper said. I had a similar problem where I was dynamically loading controls, but I couldn't get a reference to the control using Page.FindControl("controlName") Someone pointed out that I needed to keep the page lifecycle in mind. I found out I needed to make sure to load the control in the PageInit because after doing an async postback the control was still there, but not loaded in the postback so there was no way to find it. This was all in csharp codebehind and ajax though, but I'm guessing the control isn't getting reloaded.
So, as it turns out we set the PostbackUrl property on one of our buttons in control A... this caused the event handlers for control B not to fire when a button in control B was pressed.
If you create a control dynamically. Any time you fire a postback using the new created control, you need to recreated it. Just think that your application are running at a server. How can the server hold information on controls created dynamically? Don't use Page.IsPostBack to create postback. PostbackUrl is bad solution. Workarround will be need.
I can go into a little more detail ... I just lost several hours fixing my own issue similar to the issue described here. In the course of creating some search controls, I added a pair of ImageButtons and set the PostbackUrl properties on them. A few days later while testing new code, I noticed that none of my other buttons on the webform were posting back properly. They would fire a postback, but the code-behind was behaving as if every postback was an initial page request and none of the event handlers were firing.
After several hours of troubleshooting, I came across this post. When I went back and removed the PostbackUrl from those two ImageButtons, everything went back to normal. I don't know why it was causing this issue, but the fix mentioned here worked for me. I want to add that my ImageButtons were not dynamically added ... they were in the markup and this issue still cropped up. Search your markup for any controls with PostbackUrl set ... remove that (program around it if needed) ... see if your event handlers will fire properly.
I am having issues with validators not firing (No expected error messages showing) when using Page.Validate() from code behind. The validators are placed inside an Ajax updatepanel.
It seems there are downloadable Ajax versions of the validators. I am not sure if I need these or if VS 2008 SP1 has them already. When the form is posted through a button, the validators work but they don't when I do a Page.Validate() on demand.
Yes, validators do work inside an UpdatePanel, but you need to use at least SP1 of ASP.NET 2.0. If you use SP1, you do not need and should not use the "ajax version" of the validators.
More details on this subject are available here:
StackOverflow: ASP.NET Validators inside an UpdatePanel
I don't want to force an update. In certain situations, I want to validate some form elements when a user changes the value on some form element. When I user makes a change to say a radio button or a dropdownlist, an automatic postback happens. When the postback occurs, I want the validation controls to fire as if I hit the submit button.
These controls which cause a postback have 'causevalidation' turned on. Another test is in the event handler of the control which caused the postback, I have a Page.Validate().
The question is why a button postback fires the validation but not another control which caused a postback?
Maybe we can take it from the top. Can you answer these?
Are you using .NET 2.0 SP1 or greater?
Are your validator controls inside the UpdatePanel or outside?
Are you using your site with javascript disabled (very unlikely)?
Note that your validators MUST be inside an updated UpdatePanel for them to display the error messages. If they are not in an updated UpdatePanel, the validators cannot change their appearance on the browser.
Did you call Update on your updatepanel?
They were included in a update for .Net framework a while ago, so yes, you have them in VS2008 SP1. I've found a problem where the server side method for CustomValidators fires twice with no "evil" effect, but otherwise they work ok.
As for the specific problem you're having, maybe the validators aren't inside the updatepanel, or some other panel ends up being refreshed by whatever control posted instead of the one that you want? Or even some ValidationGroups are defined somewhere and only these end up being validated? It's very hard to say without seeing code.
But making sure your validators are shown is easy: MyUpdatePanel.Update() will force the refresh.
I ended up using a single custom validator and doing my own validations in code behind and setting the custom validator's error message. This way I had more flexibility and it worked.
Using Ajax, it feels like client side validation.
I have a panel on an aspx page which contains an UpdatePanel.
This panel is wrapped with both a PopUpControl Extender as well as a DragPanel Extender.
Upon initial show everything works fine, the panel pops up and closes as expected and can be dragged around as well.
There is a linkbutton within the UpdatePanel which triggers a partial postback. I originally wanted to use an imagebutton but had a lot of trouble with that so ended up using the linkbutton which works.
Once the partial postback is complete I can no longer drag the panel around.
I would love to hear suggestions on how to fix this.
Has anyone else encountered this problem?
What did you do about it?
Do you know of any other way to accomplish this combination of features without employing other third party libraries?
Take a look at when the drag panel extender and popup control extender actually extend your panel.
Chances are those extenders work on an initialization event of the page. When the update panel fires and updates your page the original DOM element that was extended was replaced by the result of the update panel. Which means that you now have a control that is no longer extended.
I don't really know of an easy solution to this problem. What will probably work is if you can hook into an event after the update panel has updated the page and extend the panel again.
Yes, it sounds crazy....It might be.
The final updatepanel does not appear to trigger anything, it just refreshes the update panels and does not call back to the usercontrol hosting it.
Any ideas?
EDIT: I got it posting back, however the controls inside the final usercontrol have lost their data...I'm thinking its because the main repeater is rebinding on each postback...Not sure where to take this one now.
I would suggest you start by removing the UpdatePanels at first, and make sure your control orgy is working correctly with postbacks. Once you have that working, try adding the UpdatePanels back in from the bottom up.
If you set the UpdateMode property to Conditional (default is Always) on both UpdatePanels it should stop the outer UpdatePanel triggering when only the usercontrols updatepanel should have refreshed.