I am facing a problem that I cannot solve!
I have two DropDownLists inside an UpdatePanel with AutoPostBack=true, UpdateMode="always", ChildrenAsTriggers="true" and EnableViewState="false".
The values shown inside the second DropDownList are dependent of the SelectedValue on the first one.
Whenever the selected value on a DropDownList, the entire page is postback. I want only the postback running inside the updatepanel.
Note: The ScriptManager has EnablePartialRendering="true".
What should I do?
Well you must have wrapped the whole page inside the Update Panel i suppose and also as i suspect UpdateMode="always" is the cukprit. Change that to Conditional. Because the update panel is going to be refreshed only on children triggers and not when anyhting and everything happens on the page.
Related
How can I make a dropdownlist with no postback - I have a dropdownlist which has code in selectedindexchanged
Basically for every indexchanged the code will connect to sql and get values then populate textboxes with values.
Here is my code
<asp:DropDownList ID="ddlSalesOrg" runat="server" Style="width: 200px;"
AutoPostBack="true" />
I want that the selectedindexchange should get hit, but it should NOT cause a full postback. If I set the AutoPostBack to false, then it won't hit selectedindexchange at all
You must choose - do you want postback or not. You can't set AutoPostBack="true" and after that stop the post backs.
If you just don't need full postback - use UpdatePanel for partial page update.
I dont get you question, do you want avoid the postback and also have the funcionality of vb/C# on every indexchanged?
Then your solution were AJAX all this time.
At this time I supose you have more knowledge about this.
But only for the register.
When you write something in the codebehing of ASP in response to an event, there you MUST be a postback (or partial postback) to achieve that code.
If you stop the postback abiously (as you said) these code is not achieved.
If you want to avoid the postback and also get some databind functionality (or any server side functionality) then you can disable the postback, handle the event in javascript, and call some AJAX function to make the databind.
key words for your next google search: ajax, dropdownlist,asp
Good luck to the next guy who has this problem.
You need to set the AutoPostBack property of the list to true.
Also, if you're populating the contents of the drop down list from the code behind (getting the contents of the list from a database, for example) - make sure you're not re-binding the data in every postback.
Sometimes people are caught out by binding the drop-down in the page load event without putting it in an If Not IsPostBack. This will cause the event not to fire.
The same is also true of repeaters and ItemCommand events.
I have two update panels and in the second update panel i have asp.net button and onclick of the button in codebehind i have disabled it like btnAddSecurity.Enabled = false;
When I disable the button i enable a cancel button before it and on cancel button when i try to enable the btnAddSecurity.Enabled = true it simply doesn't work. Both of my updatepanels updatemode is conditional. what is the problem?
thanks
I am assuming cancel button is in the different updatepanel. Then add follwing line to your button click code..
UpdatePanel1.Update();
For more information refer this..
How UpdatePanel Controls Are Refreshed
If the UpdateMode property is set to Always, the UpdatePanel control’s content is updated on every postback that originates from anywhere on the page. This includes asynchronous postbacks from controls that are inside other UpdatePanel controls, and postbacks from controls that are not inside UpdatePanel controls.
If the UpdateMode property is set to Conditional, the UpdatePanel control’s content is updated when one of the following is true:
• When the postback is caused by a trigger for that UpdatePanel control.
• When you explicitly call the UpdatePanel control's Update method.
• When the UpdatePanel control is nested inside another UpdatePanel control and the parent panel is updated.
I have an update panel that contains a repeater that calls a user control into each row. When I click a button inside the user control, the page does not refresh at all, only when I reload it completely. How can I make the update panel refresh from user control's button click?
Phairoh is correct that your button needs to successfully cause a PostBack.
There are three things that affect when a UpdatePanel is updated:
The UpdateMode property - This takes two possible values, Always and Conditional.
If it is set to Always then any postback o the page will cause the UpdatePanel to update.
If it is set to Conditional then the UpdatePanel is only updated when the UpdatePanel's Update method is called or when one of the UpdatePanel's triggers does a postback.
The Triggers proroperty - Defines which controls will cause the UpdatePanel to be updated when UpdateMode is set to Conditional.
The ChildrenAsTriggers property - This is a boolean value that determines if child controls of the UpdatePanel are automatically considered triggers without having to be added to the Triggers collection.
Because your button is in a UserControl it won't be easy to add the control to the Triggers collection or to have the button call the Update method on the UpdatePanel that is not inside the UserControl.
Because your UpdatePanel contains the UserControl's your best bet is to enable ChildrenAsTriggers. If this doesn't work try setting the UpdateMode property to Always. If this still doesn't work then Phairoh is probably correct and your Button isn't posting back.
Sometimes solving this problem not really convenient with Triggers. So here is another fancy approach which could be used even from your user controls without any knowledge about Update Panel:
var scriptManager = ScriptManager.GetCurrent(Page);
if (scriptManager != null)
scriptManager.RegisterPostBackControl(SomeControlID);
Are you sure your buttons on your user control are attempting to do a postback? I haven't used update panels in a while (and I'd actually recommend avoiding them) but if I recall correctly they will refresh whenever a postback is done within them. This means that your buttons must be Asp:Buttons (or similar controls that cause postback) and not have some kind of javascript on them that would not allow their action to continue (such as a return false).
Am I doing this correctly?
I have two dropdowns. The first is populated on form load, and it is a trigger for an updatepanel that contains the 2nd dropdown.
When I change the value in the first dropdown box, it triggers the 2nd one's updatepanel, which populates it.
However, when I select a value in the 2nd dropdownbox, it triggers itself and repopulates... so if I select the 2nd or 3rd item in the dropdown, it repopulates and selects the first item again.
Am I doing something wrong, or is this normal? Should I put the first dropdown into an updatepanel instead and have it trigger itself, and in its own trigger, populate the 2nd listbox?
It appears that changing the value in the second dropdown is causing a postback, which it then sets the value to the default or first value. Try setting the dropdown's AutoPostBack property to false and EnableViewState to true.
Use the ASP.NET Ajax Control Toolkit CascadingDropDown instead.
EDIT: You need to set your UpdateMode=Conditional and control when your UpdatePanel's should update, by calling UpdatePanel2.Update().
I had this problem once.
This is a problem for update panel plus dropdown autopostback
By default ViewState for page is stored,so you do not need to change ViewState for control.
First,Change your UpdatePanel's UpdateMode property to Conditional UpdateMode="Conditional".This ensures that you can control postback since your dropdown always postback when you set AutoPostBack to true.
Second is in your method which you bind datasource into dropdown,after databinding is done.Update your panel by calling Update method of UpdatePanel updPanel.Update(); by
dropdown.DataSource = source;//I presume
dropdown.DataBind();
updPanel.Update();
Hope this helps.
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.