I'm doing some straight up asynchronous calls from javascript using the XMLHTTPRequest object. On success, with certain return values, I would like to do an asynchonous post back on an update panel and run some server side methods. This is about how I'm implementing it now:
<script language="javascript">
function AjaxCallback_Success(objAjax) {
if (objAjax.responseText == "refresh") {
document.getElementById('<%= btnHidden.ClientID %>').click();
}
}
</script>
<asp:UpdatePanel ID="upStatus" runat="server">
<ContentTemplate>
<asp:Button ID="btnHidden" runat="server" style="display: none;" OnClick="SomeMethod" />
<asp:DropDownList ID="ddlStatus" field="Orders_Status" parent="Orders" runat="server">
</asp:DropDownList>
</ContentTemplate>
</asp:UpdatePanel>
This has to do with work flow. If while you are working on an order, someone invoices it, then the options available in the status drop down actually changes. So a timed even checks for changes and if there is a change, which wouldn't normally happen, the update panel posts back and the drop down list gets re-bound to a new data table based on various return values from the ajax response text.
My original code is actually much more complicated than this, but I've abstracted just enough to make my concept clearer. Is there a better, cleaner way to do this by dropping the hidden button and making a straight javascript call that will cause an update panel to asynchonously postback and run a server side method?
Be very careful with UpdatePanels, they can be very heavy if not used properly as I explain here.
But the JavaScript for submitting a form is:
__doPostBack('eventTarget','eventArguments');
So in your example you'd have something like:
__doPostBack('<%= btnHidden.ClientID %>','');
You can remove the hidden button and call
__doPostBack('upStatus','');
This will cause an asynchronous update for that update panel
Related
I've looked everywhere and read everything and nothing I do seems to work so I'll ask this question again.
I have an ASP.NET WebForms application that has a page that can collect multiple pieces of data (textboxes and dropdowns) in order to then perform a search. Once collecting all of the data from the user, the user can click the "Search" button to initiate the search. I'd like the user to also be able to simple hit the Enter button and have the search initiate. I cannot seem to do this successfully.
I've tried the DefaultButton approach at the Panel level as all of the ASP.NET controls are inside of a panel. No luck. I've tried the JavaScript function approach (defaultEnterKey) checking for event.keyCode === 13 and just trying to add an attribute to one of the text boxes (onkeydown) in the code behind just to get it to work. Nope.
I'm obviously missing something.
Well, you could first try at the form level.
so in the form tag, say try this:
<form id="form1" runat="server" defaultbutton="Button3">
Give the above a try - even with a update panel, and then a panel inside that update panel, the above should work.
So try the form level setting - that is the outer most form that wraps everything in that given page.
Edit: the whopper and Mount everest detail been noted that the page has a master, and thus of couse no form tag exists.
Thus, I suggest this:
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:Panel ID="Panel1" runat="server" DefaultButton="Button2" >
your markup here
</asp:Panel>
</ContentTemplate>
</asp:UpdatePanel>
You can simply cuse jQuery to bind a function on KeyPress and check if it is the Enter key. If so then do something with it.
The return false is needed to prevent the form from doing a PostBack.
<asp:TextBox ID="TextBox1" runat="server" CssClass="CaptureEnter"></asp:TextBox>
<script>
$('.CaptureEnter').keypress(function (e) {
if (e.keyCode === 13) {
alert('Enter was pressed! Start searching for: ' + $(this).val());
return false;
}
});
</script>
I'm new with working with ASP.net and .ascx, and now I've seen a button that calls a method by 'OnClientClick' So the code looks like this:
<asp:Button Text="Save" OnClick="BtnSave_Click" OnClientClick="isBusy();"/>
Now I want that the method only calls at certain definitions declared in the same .ascx file. And thus I thought that an if-statement inside the ascx would work. So I've already tried attempts like OnClientClick="if(Text.Length <= maxlength) { isBusy(); } but that caused the line to not respond at all.
Currently I'm wondering if an if-statement in this situation is actually possible.
it is doable. but you need to make sure your js is correct.
in your question, what is Text.Lengh ?
whatever, if you want block the server side postback, then return false in your onclick JS, that will completely mute the postback event
for example
<asp:button runat="server" onclientclick="return false;" />
this button will never post back
I have the following code in my aspx file:
<button type="button" id="btnAskQuestion" runat="server" onserverclick="btnAskQuestion_Click">Ask Question</button>
I've tried every combination of onclick="return false;" and onclick="preventDefault()" I can think of, including putting them in the javascript function that gets called. Everything I try has one of two results: either I get a postback, or the server side code (btnAskQuestion_Click) never executes.
Any idea what I might be doing wrong?
You cannot execute server-side code this way, using onserverclick causes postback.
If you wish to prevent full page refresh and still execute server-side code, you have to call a client-side JS function via onclick and execute an AJAX call from there.
Another alternative is to use your button as a trigger for UpdatePanel - this way only partial postback will be performed.
Try using the property UseSubmitBehavior="false" in the button markup.
or you can use a "trick" :
Markup
<button onclick="myFunction()">Click Me!</button>
<div style="display:none">
<asp:Button runat="server" id="btnButton" .../>
</div>
js
function myFunction()
{
if (true statement)
$("[id$=btnButton]").click();
else
alert("false");
}
What this does is that you handle stuff with normal markup and do the logic using js. And you can trigger a click of the button that do something in the server.
There're OnClick, that fires on server and OnClientClick that fires on client browser. You should do this:
<asp:Button ID="btnAskQuestion" runat="server"
OnClick="btnAskQuestion_Click"
OnClientClick="return myfunction();">Ask Question</asp:button>
If myFunction returns true, then you will have a postback to the server.
My answer is appropriate only for ASP:Button, not the button control you are working with. Given the choice, I'd switch to ASP:Button.
You're looking for OnClientClick. If you put your JavaScript code there, it will kill the PostBack before it can hit the server.
On the other hand, if you're looking to execute server code without a PostBack, that's impossible. The PostBack is what triggers the server to act.
I am having a weird issue with a web form I'm working on that seems related to some async stuff going on. Basically, I need to do the following:
UserInputPanel.Visible = False
ProgressPanel.Visible = True
ResultsSet = New DataSet()
GetResults(ResultsSet)
FillOutput()
ProgressPanel.Visible = False
OutputPanel.Visible = True
This code all runs as the result of clicking a button on the WebForm. The call to GetResults(ResultsSet) is a lengthy one, thus the need to show the panel ProgressPanel. Problem is, the call to GetResults is happening before my ProgressPanel actually shows. If I comment out the call to GetResults and the lines that follow, then ProgressPanel shows up no problems. How can I force the first two lines to execute and show on the page before the call to GetResults happens?
It sounds like you need to use the UpdateProgress control instead of trying to trigger your own. When your form button is clicked, all the code on the server side click handler runs before any response is sent to the client.
You need something like this instead of your ProgressPanel:
<asp:UpdateProgress ID="UpdateProgress1" runat="server">
<ProgressTemplate>
</ProgressTemplate>
</asp:UpdateProgress>
The contents of the ProgressTemplate will automatically be displayed whent the asynchronous postback starts, and then will hide once it is complete.
To hide the UserInputPanel, create a javascript function like the following (use jQuery or some other client-side js framework for more robust cross browser code):
function hideUserInput() {
document.getElementById('<%=UserInputPanel.ClientID%>').style.visibility="hidden";
}
and attach this function to your button's OnClientClick property:
<asp:button id="YourButton"
text="Submit"
onclientclick="hideUserInput()"
runat="server" onclick="YourButton_Click" />
I have an update panel in a repeater
(Edit: I removed Runat and Id attributes to make the post look cleaner)
<asp:Repeater>
<ItemTemplate>
<asp:UpdatePanel UpdateMode="Conditional">
<ContentTemplate>
<asp:LinkButton onclick="btnCallback_Click" />
</ContentTemplate>
</asp:UpdatePanel>
<asp:UpdateProgress DisplayAfter="0">
<ProgressTemplate>
<img src="spinningProgress.gif" />
</ProgressTemplate>
</asp:UpdateProgress>
</ItemTemplate>
</asp:Repeater>
The idea is here that you click the LinkButton and it calls back and performs a server side action for that data item. This works perfectly fine for one item. However, if I click the button for every item without waiting for the previous update panel to finish the call back, it appears to cancel the previous callback.
Can UpdatePanels not perform call backs at the same time? Is there anyway I can make it so you don't need to wait before clicking on the next button?
Every AJAX request performed via UpdatePanel cancels any previous one (if previous is still running). This is how it is built. UpdatePanel AJAX request passes portions of ViewState along with request. It is impossible (at least very hard) to reconcile multiple arbitrary viewstates brought back by concurrent ajax calls. I heard that this was the primary reason MS chose to build it that way.
EDIT: use jQuery and have fun :-)
I had the same problem before. But i finded out that making some tricks can allow you to implement multiple ajax calbacks in different microsoft update panels.
function ProcessCallBack(uniqID)
{
var prm = Sys.WebForms.PageRequestManager.getInstance();
//checking if there is somewhere perforimg of callback
if (prm.get_isInAsyncPostBack())
{
setTimeout("ProcessCallBack()", 1000); //here we move execution of callback
//for 1 sec forward
}
else
{
__doPostBack(uniqID,'');
}
return false;
}
So you must add calling of that function to your button or control on client-side click. uniqID is the unique identifier of server control, you can get it on server side.
So enjoy, and remember that everything is possible, but for some is needed a lot of time todo :-)
I was thinking about that, why guys from microsoft didn't implement such thing :-)