I have a few controls that inherit from ASP.NET buttons and use onserverclick.
If the user clicks twice, the button fires two server side events. How can I prevent this?
I tried setting this.disabled='true' after the click (in the onclick attribute) via javascript, but that blocks the first postback as well.
See this example for disabling control on postback. It should help you do what you're trying to achieve.
http://encosia.com/2007/04/17/disable-a-button-control-during-postback/
You don't necessarily want to show the button disabled on postback. You want to make sure they don't accidentally submit twice. So disabling or hiding the button as a result of a server-side action is already too late in the game. By this point the 2nd request is already on it's way. You need to either do it with javascript or make sure your server side code won't run twice.
In case of an updatepanel and a button inside a FormView-Template I use the following approach:
// Using that prm reference, hook _initializeRequest
Sys.WebForms.PageRequestManager.getInstance().add_initializeRequest(InitializeRequestBuchung);
// Abfangen von Mehrfachklicks auf Buttons für asynchrone Postbacks im Updatepanel
function InitializeRequestBuchung(sender, args) {
var arrButtonIds = ["ButtonInsert", "ButtonUpdate"];
// Get a reference to the PageRequestManager.
var prm = Sys.WebForms.PageRequestManager.getInstance();
if (prm.get_isInAsyncPostBack() & jQuery.inArray(args.get_postBackElement().id, arrButtonIds) > -1) {
args.set_cancel(true);
}
}
This cancels the following postback if an async postback is currently still active. Works perfectly.
Someone else said this somewhere on here a few days ago, and I concur - use javascript to simply hide the button instead of disabling it; you could show a "spinner" image in its place, which lets the user know what is going on.
Instead of hiding, what I have done is swapping buttons using javascript. Show another greyed out image on the click of the first button.
Set the Button property UseSubmitBehavior to false. Then create an OnClientClick function that disables the button.
It would look something like this:
<script type="text/javascript">
function disableFunctn(button){
button.disabled = true;
}
</script>
<asp:Button ID="button1" UseSubmitBehavior="false" OnClientClick="disableFunctn(this);"/>
fastest cheapest way:
<asp:Button ID="button1" UseSubmitBehavior="false" OnClientClick="this.disabled=true;"/>
You can also try for example btnSave.Enable = false; when the button is hit and before the processing for the button is done in the Click Event routine. If you need it to be reset to allow it to be enabled have a separate button that resets the button for reuse.
Another method is to set the button with verification so that the user is asked if they want to Save, it should pop up both times.
Yet another method would be to flag the first occurrence then set a popup for the second to verify a second or subsequent usage.
Related
I have a page some 2 ASP Tabs and with an UpdatePanel on the first tab. Inside the update panel (on page_load), I dynamically create a table that contains rows with cells for an image, some text, and an ASP:Button. I'd like the button, when clicked to switch tabs from the first to the second. Instead, all it does is refresh the updatepanel it resides in. How can I stop it from behaving that way? How do I get it to perform a function of my own design, instead of posting?
Thank you,
You can add javascript click event and stop it to do post back by returning false;
In Code behind, where you add button dynamically.
btnChangeTab.Attributes.Add("onclick", "return YourJavascriptFunction();");
In Client side.
<script type="text/javascript">
function YourJavascriptFunction()
{
//Your javascript code here
return false; //the will stop from postback
}
</script>
There is an event onSelectedIndexChange for DropDownList in ASP.NET which triggers when a selected index is changed for a dropdown.
I have encountered a situation where I need to trigger similar kind of event when SelectedIndex of DropDown does not change upon selection.
I am totally puzzled what to do in such a case?
Any help/references will highly be appreciated.
Thank you.
I think that is normal. The event is SelectedIndexChanged and you said you selected the same item that was previously selected before. So the index remains the same, not changed, and the event won't fire. May be you look at OnClick.
The issue is that you have not changed the index when you clicked the second time, so the dropdown is still waiting for you to change it
Assuming you have another server-side control on your page that causes a postback, you could write a routine in the postback event for the other control that compares the current selection with the previous selection and fire a custom-event (or the routines you want to happen) if the value has not changed.
That said, I have to imagine there's an easier way to accomplish the overall goal you're trying to achieve, but you'll have to be a little more specific in your question.
UPDATE
I have to assume that you are using the value from the dropdown when you are processing the form. Why not start off with the dropdown hidden and the linkbutton shown? Just select a default from the dropdown list and allow the user to change it as needed.
Here's a fiddle showing that behavior: http://jsfiddle.net/rjaum/
That's fairly easy.
You can achieve this using javascript/jquery/server side code etc. Assuming user does click the control.
Something like this on pageLoad
PageLoad()
{
YourDropDownList.Attributes.Add("onclick","javascript:CallHelloWorld();return false;");
}
Then on server side you can decorate a method with WebMethod attribute
[WebMethod()]
public static string HelloWorld()
{
return "Hello foo";
}
On your client side aspx you can use jQuery to call your webmethod
<script language="text/javascript">
function CallHelloWorld()
{
// Call HelloWorld webmethod using jQuery $.ajax
}
</script>
Edit
You can use a radiobutton list instead of dropdownlist. That way, on client side you can check the event when the radio button is clicked that it is checked or not (if its checked fire your event).
Edit
Also try looking at this thread if you want to use dropdown list specificallyFire event each time dropdown list is selected with JQuery
assign an a event handler to the selected index changed event and set autopostback to true
in markup
or code behind
mydropdownlist.SelctedIndexChanged += NameOfMethod
the handler is then defined like this
protected void NameOfMethod(object sender, EventArgs e)
{
//your code here
}
update
by definition the selectedindexchanged event would only fire when the index changes. if you want to force the postback that will require some javascript. here is an example of how to do that with jquery
$(function() {
$('select').change();
});
Now I could be going about this the wrong way so if there is a better solution please post that as well. What I am trying to do is disable a button once it is clicked to prevent double clicks. In the past I have done my just disabling the button onclick but with webforms I am running into a little bit of a snag because there is validation on the page so I need that to fire and I need to post back.
So I have the following JQuery function to make a button disable itself on click. Here is the JQuery:
jQuery.fn.disableOnClick =
function()
{
return this.each(function()
{
$(this).click(function()
{
$(this).attr('disabled', 'disabled');
return true;
})
})
};
Intended usage would be:
$(document).ready(function()
{
$("#<%= btnSomeButton.ClientID %>").disableOnClick ();
});
This doesn't work... the button always disables, the validation is ignored and the postback doesn't even happen. I would assume because I am overwrittin the click handler. Suggestions?
UPDATE: I have tried just a basic function that is connected to the 'OnClientClick' of the button to do:
// In my Page_Load
btnSomeButton.OnClientClick = "return DisableButton('" + btnSomeButton.ClientID + "');";
// Javascript function
function DisableButton(id)
{
var bButton = $("#" + id);
if (Page_ClientValidate())
{
$("#" + id).attr('disabled', 'disabled');
__doPostBack(id, '');
}
}
This works as expected in a non master page setup but when I try to use it with a page that has a master page, the postback occurs and the Page_Load fires but the button click handler never gets called. It's like the __doPostBack is not sending which control event to fire correctly.
Any suggestions for changes or even a whole different approach?
One idea for a different approach (disclaimer: this is not a fully baked solution) is to go from the submit action of the form instead of the click handler of the button.
The validation all happens through the submit handler of the form. If everything checks out, the form is allowed to submit. If you could hook into that process, then when the form started to submit for real, you could find all buttons with the class DisableOnSubmit and disable them.
Validation could take some time, however, and some people (annoyingly) seem to like to double-click on web forms, so it might be best to blend the approaches. Disable the button immediately with a click handler, then if validation fails, re-enable the buttons that were disabled.
EDIT In response to comments
This description could be turned to be more like the signature in the question (where any button could be made to be click-once regardless of its CSS classes).
Create a jQuery extender where the buttons that fit the selector are given an onClick handler and (if not already done) the hook is added to the validation being complete. The onClick handler adds the clicked button to a collection of "currently in click evaluation" buttons. If validation succeeds, the form submits normally. If validation fails, the buttons in the collection are re-enabled and removed from the collection.
For the evil update panels, you might want to look into specifying these events with live bindings (used to be a plugin, but I think it's now part of the jQuery core depending on which version you're using) so that the event handlers are reregistered when the partial postbacks complete.
I get the feeling you can use GetPostBackEventReference to do the actual postback once you've done your validation dance.
Edit Oops, forgot the other half of the answer :-)
As for the double postback, I've used Postback Ritalin by Dave Ward in the past to curtail those pesky hyperactive users.
Add this to your startup code (ready event handler):
var elemButton = $('#<%= Button1.ClientID %>');
var fnExistingHandler = elemButton[0].onclick;
elemButton[0].onclick = function()
{
fnExistingHandler();
if (!Page_BlockSubmit)
{
$(this)
.hide()
.after('<input type="button" value="Please Wait..." disabled="disabled" />');
}
};
Basically you append new code to existing click handler. Note checking global variable Page_BlockSubmit.
Instead of disabling submit button you can hide it and immediately insert disabled button in its place. Because this happens very quickly it will look as button becoming disabled to the user. Details are at the blog of Josh Stodola.
Edit: fixed client validation.
Haven't tried it but what about something like this:
$("input[type=submit]").live("click", function() {
$(this).hide().clone().insertAfter(this).show().attr("disabled", "disabled").val("Please wait...");
return true;
});
This will ensure a submit button isn't disabled which ASP.NET doesn't like.
Some weird stuff is happening, I am converting an application that used to use javascript to open another web page in a tiny window for data input to use a ModalPopupExtender.
It seems to work fine, but in the OK event, when I do txtData.Text (the textbox in my modal popup), it comes back with a comma before the data, so if you type "Rabbit", it comes back as ",Rabbit".
Also when I use it multiple times, in another place where I might click to show it, and type "Fish", it starts coming back with stuff like ",Rabbit,,Fish"
I don't know why or how to stop it from doing this... any ideas?
Same here. No clue for why it happens. Every postback initiated by buttons within the panel adds commas and previous values to all text fields.
Hooking into TextBox.Text setter revealed that the corrupted data comes from postdata collection. So it means that just before postback the ModalPopupExtender corrupts the data.
P.S. I'm not using UpdatePanel, but regular Panel so there are no triggers associated with buttons.
Updated: Solution found.
The problem seems to go away when rolling back to May's release of AjaxToolKit (http://ajaxcontroltoolkit.codeplex.com/Release/ProjectReleases.aspx?ReleaseId=27326).
Just sharing this solution to everyone on this problem. Try not to use asp control instead use html.
*<input type="text" id="txtID" runat="server" class="myClass" />*
this works fine for me.
Thanks,
I also found a forum indicating that it may be standard html behaviour for when there are multiple controls on the form with the same name. This in mind (and assuming there is a bug in the ajax controls) The way I coded around it was to add in my Page_Load the following kind of statement for each of my textboxes.
string[] vals = txtValue.Text.Split(Convert.ToChar(","));
txtValue.Text = vals[vals.Length - 1];//It appears my latest value was always in the last item
Since the form load happens before the button event I sort out my fields before they get to the event that deals with their values.
I had a similar problem, having a jQuery Dialog inside an UpdatePanel. As I could read on different sites, the problem is caused by duplicates inside the DOM tree.
In the end I found a very simple solution. I assign the dialog to the div, then open or close it by JavaScript and then run this little peace of code to remove the duplicates:
var count = $(".dialog").length;
for (i = 1; i < count; i++) {
$(".dialog").first().remove();
}
EDIT: it turned out not to be SO simple. In the end, my code looked like this:
In document ready (and also asynchronous page calls):
function AddDialog() {
var dlg = $(".dialog").dialog({ autoOpen: false });
dlg.parent().appendTo($("form:first"));
var targetSelector = ".myDialog"; // watch out: can't use ID here!
if (mustOpenDialog) {
$(targetSelector).last().remove(); //-- remove last copy
var dlg = $(targetSelector).dialog({ autoOpen: true });
var count = $(targetSelector).length;
for (i = 1; i < count; i++) {
$(targetSelector).last().remove();
}
}
if (mustCloseDialog) {
$(targetSelector).dialog("close");
var count = $(targetSelector).length;
for (i = 1; i < count; i++) {
$(targetSelector).first().remove();
}
}
}
In my complete code, mustOpenDialog and mustCloseDialog are set in codebehind.
I had the same problem with previous values coming back comma separated. It seemed that my ok button was inside the update panel and I had it in the triggers section aswell. Removing the button from the triggers section of the updatepanel solved the problem.
best regards - Tobias
My answer was similar to Smarty's. My page looked like this...
<UpdatePanel>
<GridView>
<Button> <-- These buttons fire modal popup programmatically.
<Button>
<Button>
</GridView>
<ModalPopup>
<HiddenField> <-- Dummy target of modal popup.
</UpdatePanel>
The fix was to change it to this...
<UpdatePanel>
<GridView>
<Button> <-- These buttons fire modal popup programmatically.
<Button>
<Button>
</GridView>
</UpdatePanel>
<ModalPopup>
<HiddenField> <-- Dummy target of modal popup.
I had to register each button as a postback control with the scriptmanager on the gridview rowdatabound event. The down side is that I have more full postbacks. But, it solved the problem.
This is pretty late reply, but I am documenting it here so that other may benefit.
My Scenario
Open user control inside jquery dialog on button click. This user control had update panel inside it and few textboxes. First time open the dialog, it worked like charm. On subsequent clicks to open the dialog, I noticed a weird behavior. I had few textboxes inside the user control(inside update panel). On any partial post back, the text of textboxes changed to current text, current text. If the value of textbox was fish, then upon any partial postbacks its changed to fish, fish.
The reason for this was I was using jquery to open the dialog. I also appended the dialog to form upon the click of the button.
dlg.parent().appendTo($('form:first'));
So on subsequent clicks multiple user controls where appended to DOM and hence while building the post back data, there existed more than one control with same id and hence there values where appended using "," - comma.
So my solution was simple, while closing the dialog, I just removed it from DOM
I got hint from following link. Posting it here for future reference
here
For some reason it doesn't seem to happen if the textbox is set to ReadOnly.
I'm thinking there could be a workaround by displaying an editable textbox to the user, catching the keystrokes to it, and updating a readonly textbox that is hidden from the user.
Still a bit messy, but I can't roll back to May's release because there's another bug in that release with the ComboBox that I need to avoid!
UPDATE:
As a bit of background, I have a user control (ascx) inside my modal popup because I need to reuse it. The ascx has to handle the user's input itself (the containing page doesn't know what's going on inside the control) so when the user clicks a button I do a callback and process the data. If a successful result is returned to the client callback function then I simulate a click of what the containing page thinks is the "OK" button which is actually invisible to the user.
I've changed my code to add a hidden, readonly textbox and copy the text from the original textbox into the new one every time the text changes.
<asp:TextBox runat="server" ID="txtName"></asp:TextBox>
becomes
<asp:TextBox runat="server" ID="txtName" onchange="document.getElementById(this.id + 'RO').value = this.value"></asp:TextBox>
<asp:TextBox runat="server" ID="txtNameRO" ReadOnly="true" style="display:none;"></asp:TextBox>
then when passing values back in the callback instead of getting the value of txtName, I use txtNameRO.
I don't think this will help if you're doing a postback, but you could add a callback before the postback like I have. Hopefully this will help someone anyway!
I had this issue and lost quite a bit of time on it and found that it was caused by an extra tag hiding out that I forgot to remove when changing markup.
Make sure on the .aspx page all tags line up correctly.
<div>
**Lots of code here**
</div> <-- That guy owes me a vacation!
</div>
I have successfully implemented a complete hack based on Jen's response. I use an asp:HiddenField to hold the value I want to post back, and I populate it with a pure HTML input box
<asp:HiddenField ID="txt" runat="server"/>
<input type="text" onchange='document.getElementById("<%= txt.ClientID %>").value = this.value;' />
This is lighter weight than Jen's solution as you're still only posting back one server control.
BTW, this is a very significant bug in the Ajax Toolkit. You can vote and comment on it here:
CodePlex Issue
Pretend you're in Chicago. Vote early, vote often.
For me the solution was to get the modal poup out of the main update panel. Once I did that the commas went away. If you truely need an update panel inside of the modal popup, create one of it's own inside that panel.
I did not need to roll back to previous version of the toolkit.
I have been trying to solve this for a day now and some very helpful person in my office has come up with a terrific solution!
We moved the ModalPopUpExtender and subsequent pop up panel controlled by the extender to ouside of the outermost UpdatePanel on the page, created a fake button and gave the ID of the fake button to the TargetControlID property of the ModalPopUpExtender.
<asp:Button runat="server" ID="dummyButton" CausesValidation="false" Style="display: none" />
<cc1:ModalPopupExtender ID="ModalPopupExtender1" runat="server" TargetControlID="dummyButton" CancelControlID="CancelPopUp" PopupControlID="PanelID" BackgroundCssClass="modalBackground" />
Inside my forms/page where the PopUp extender and panels used to be, I created an OnClick event on the button that we used to use to trigger the ModalPopUpExtender.
<asp:ImageButton ID="ButtonID" runat="server" Text="Add" ImageUrl="~/Images/Add-32-1-small.png" OnClick="LoadPopUp" />
On my button that triggers the ModalPopUpExtender, I have created an OnClick event called "LoadPopUp" - in LoadPopUp in the code behind I simply put ModalPopUpExtender1.Show();
protected void LoadPopUp(object sender, EventArgs e)
{
ModalPopupExtender1.Show();
}
I had the same problem except I am not using the AjaxControlToolkit or update panels. My problem was solved by moving the <form> tag from the ASP.net master page to the page where the textboxes are. May help someone.
has same problem and i found the solution here: http://ajaxcontroltoolkit.codeplex.com/workitem/26259
The problem is ajax last version, just INSTALL year 2009 ajax version and modalpopup will work fine with your actual code.
Tuve el mismo problema y encontré la solución en el link que indico arriba.
El problema viene con las versiones recientes de ajax, simplemente instala la version del año 2009 y el modalpopup funcionará bien con tu código actual.
The solution is to get the modal popup out of the main update panel. Once Do that the commas will go away. If you truly need an update panel inside of the modal popup, create one of it's own inside that panel.
I have a table that is created in a DataList in ASP.Net. This table has three fields of text, then a field with an edit button, and a field with a delete button. When a person clicks the delete button, it posts back, deletes the items, and then binds the DataList again. The DataList is in an UpdatePanel so the item smoothly disappears after a half of a second or maybe a little more, but what I'd really like is for the row to slide out (up) as soon as they hit the delete button, and then have it delete the item on the post back.
I can make the row slide out with jQuery, but the postback gets in the way. How do you deal with that?
You can use page methods in asp.net to send a request to the server without doing a postback. They are very simple to use and you can do whatever effect you like when the ajax call is completed (you get a function called on success).
If you want to stick with the post back one solution is the following:
<asp:Button id="myButton" OnClientClick="return fadeThenAllowSubmit()" ... />
and in js something like:
var allowSubmit = false;
function fadeThenAllowSubmit() {
if (allowSubmit) return true
// do the jquery stuff that will be completed in, let's say, 1000ms
setTimeout(function() {
allowSubmit = true
$("input[id$=myButton]").click()
allowSubmit = false
}, 1000)
return false
}
It's a bit of a hack, the idea is to cancel the postback initially, do some stuff then set a timer where the postback will be enabled. The big problem with this approach is that the fade effect and the actual delete are independent (in case of an error you still get the fade effect).
have you tried looking at any of the Ajax control toolkit items? I believe there are some controls in there that will head with client side (java) code if your not extremely familiar
I would use client side Javascript to manually scale the "opacity" CSS property down to zero, then mark the element as "display: none" then submit the post-back.
I believe that in Internet Explorer, you need to use the "Filter" CSS property to do this as it does not support opacity.
You could just code up a routine to set both properties and that should cover all the major browsers.
Register the handler for form "submit" event.
$("form").submit(function() {
// if user initiated delete action
// do your thing with deleted row (effects, etc.)
// after you're done with it, submit the form from script
// (you can queue the submission after the effect)
// the submission from the script won't trigger this event handler
return false; // prevent submission
}
Preventing form submission is necessary to avoid interference with the effects you want to perform. After they are finished, you are free to proceed with submission.