I am developing my first asp.net website, my requirement is to refresh DropDownListB at SelectedIndexChanged event of DropDownListA, I have set AutoPostBack="True" for DropDownListA. Now the problem is whole web page gets refreshed, its unnecessary for me, is there any other technique that i can use to refresh only that control or only that panel rather than refreshing whole page?
Put the dropdowns inside
<asp:UpdatePanel ID="up1" runat="server">
<ContentTemplate>
// Dropdowns
</ContentTemplate>
</asp:UpdatePanel>
and include <asp:ScriptManager ID="sm" runat="server"></asp:ScriptManager> at the top
1- You can simply place the dropdown in an UpdatePanel, this will avoid a complete post back.
You can get more details on UpdatePanel here
2- You can use jQuery AJAX to fetch the data in JSON format and bind it to the dropdown list, this approach is more efficient but little complex in comparison to UpdatePanel
You can find so many articles on this if you search this on google , like
[EDIT]
You can find a similar implementation here
Related
My code in my MasterPage is causing a full page_load on my content pages every 5 seconds. Sadly, that means it is breaking some of my content pages and how they are programmed. My hope was that a separate UpdatePanel would allow only that region to be updated and not refresh the other UpdatePanels and resources on the content pages.
I've attempted moving the Timer out of the UpdatePanel, changing the UpdatePanel to UpdateMode="Conditional" and even using a third party AjaxPanel (Telerik).
All results are the same, the content page reloads every 5 seconds clearing the title template (Shown below) and sometimes breaking some functions on the site.
Until I can figure out a way to ONLY have the literal update without reloading the other resources I have to leave the Timer disabled.
I'll be happy to post more code if needed, but I didn't want to provide information that may not have any importance.
MasterPage - Site.Master
<title><%: Page.Title %> - My ASP.Net Site</title>
<asp:UpdatePanel ID="UpdatePanelMenu" runat="server">
<ContentTemplate>
<span>Tickets<asp:Literal ID="LiteralUnassignedTickets" runat="server"></asp:Literal></span>
<asp:Timer ID="TimerAutoRefreshMenu" runat="server" Interval="5000" Enabled="true"></asp:Timer>
</ContentTemplate>
</asp:UpdatePanel>
if you have to use update panels make the update panel update conditional and set the timer as an asynchronous trigger(very important).
update panels are even worse when they are on master pages then when they are on the content page
a better option for minimal change is setTimeout to a function that does an ajax call to update the number of unassigned tickets. you can grow this to update a whole bunch of fields/elements using a json object. Plus the techniques can be very useful if you move to MVC.
here is some code in my page :
<asp:UpdatePanel ID="UpdatePanelEQSelector" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<uc12:EQSelector ID="custEQSelector" OnEqChange="custEQSelector_OnEqChange" runat="server" />
</ContentTemplate>
</asp:UpdatePanel>
Inside my user Control, I'm asked to add a fileuploader.
After coding it simply, I tested and my fileuploader is always empty.
I've searched a while and discovered that it was a normal behavior.
The solution to make it work is to add a PostBackTrigger for the updatePanel.
When I tested it in my aspx page, I achieved to do it and my fileUploader had the file.
Then I tried to add it dynamically (to finally do it in my control), it worked with that :
PostBackTrigger trigger = new PostBackTrigger();
trigger.ControlID = this.btnTest.ID;
this._UpdatePanelEQSelector.Triggers.Add(trigger);
But I can't manage to make this code work in my control (I passed my updatePanel as a parameter to my control set in Load, the fileUpload is always empty)
Do you see a solution ?
Thanks
Does it postback, but leaves the control empty? or is it not posting back at all. If it's not posting back at all I'd add this
ScriptManager.GetCurrent(this).RegisterPostBackControl(btnTest);
to the page_load of the user control.
If it is posting back, but the control is empty, then I'd wager there is probably some dodgy html somewhere on the page and the values are getting lost.
I am getting this error "An extender can't be in a different UpdatePanel than the control it extends". what could be the reason and how to tackle this problem.
You are using an AJAX ToolKit Extender Control to extend the functionality of one of your ASP.NET Controls. You have placed the Extender Control in a different UpdatePanel than the one the Extended Control resides in.
Both Extender and Extended controls must reside in the same UpdatePanel to avoid this exception.
Both Extender and Extended controls must reside in the same UpdatePanel to avoid the exception, this solved my problem.
I had an extra UpdatePanel that was giving this error, so I just had to remove the extra update panel lines of my aspx web page code.
What it says really - you've got an extender control that relates to a control that is in a different updatepanel. This means the extender is unable to act properly on the control it extends. You'll need to move your extender to be within the same updatepanel as the main control
In my case I was using button...outside the Update panel as below shown....
<asp:Button ID="btnClub" runat="server" Text="Club" OnClick="btnClub_Click" />
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
I just solved it by putting the <asp:Button ID="btnClub" runat="server" Text="Club" OnClick="btnClub_Click" /> inside the
update Panel
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:Button ID="btnClub" runat="server" Text="Club" OnClick="btnClub_Click" />
Here you make your panel code
</ContentTemplate>
</asp:UpdatePanel>
Reason :Your iD is mis matching Ex:Text box id or dropdown id mismatch in Calender extender or RequiredFieldValidator
Ex:
Hear Id Value And Target Control Id Must Match .....
Check for controls with extenders that are have the same ID especially if you copy pasted from another form
Hi I got the solution of my problem by myself. The problem occurred when the target
control id of the extender control was different from the control it
had extend inside update panel. I resolved this proble a long time
back and replying now.
I am working in asp.net 3.5 and have some issue of update panel.I have some html content and Formview control in a page. I want to hide the html content when there is no data in the Formview and to show when there is data in the Formview control. My Formview control is in the updatepanel and it it is bind to SqlDataSource and Formview binds on some criteria.
If somebody know how to solve this issue then please help me.
If you want the HTML content to be hidden after an Ajax postback, it will need to be in an UpdatePanel, either the same one your FormView is in, or a separate one.
If it's in a separate one, you'll need some way of forcing it to update when the FormView updates. You can either do this in some code-behind, calling the Update() method of the UpdatePanel, or by adding an AsyncPostBackTrigger to the UpdatePanel containing the HTML, maybe using the DataBound event of the FormView.
Also, to easily hide the HTML content, put it in a Panel, and use the Visible property.
An example of the trigger:
<asp:UpdatePanel ID="updatePanel" ... runat="server">
<ContentTemplate>
...
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="formViewId" EventName="DataBound" />
</Triggers>
</asp:UpdatePanel>
This issue simply resolved using the putting all the html content in the Updatepanels and on UpdatePanel_preRender event of Updatepanels check that if Gridview has data then show html content otherwise hide
We have an issue on our page whereby the first time a button posts back (we have ASP.NET ajax to enable partial updates) nothing happens, then on every subsequent click, the information is updated as if the previous event fired.
Here's the code for the page. The events are button clicks fired from within the table. Which is rerendered at the backend.
<asp:ScriptManager EnablePartialRendering="true" ID="scrptMgr1" runat="server">
</asp:ScriptManager>
<asp:UpdatePanel runat="server" ID="folderContainer">
<ContentTemplate>
<asp:Table id="FolderTable" CssClass="FolderTable" runat="server" CellSpacing="0"></asp:Table>
</ContentTemplate>
</asp:UpdatePanel>
Any ideas?
Thanks.
Did you try an HTML table, with or without runat="server" ?
Do you add or remove controls inside the table in the postback?
Inspired by Robert's answer:
In which event handler do you build your table? If you build it in Page_Load without checking IsPostBack), then the button's click event has not been handled yet.
You need to build the table in the button click handler.
Your table is probably being populated too late in the page lifecycle. Try creating the table in PreInit.