I wonder if there is way to run JS code whenever a asp.net page is contacting the server.
I.e. I'm looking for a general event handler that is triggered whenever a call to the server is made for runat="server" components.
I know there's a way to get jQuery.ajax() to run JS code before and after a call to the server is made, but I'm not sure how to do it in asp.net. Especially, since this projects uses a lot of custom components.
The goal here is to show some kind of loading image when a button is clicked, to prevent the user to click a button twice and also to show the user that the system is working.
If the click causes the page or an updatepanel to refresh, I'd only like to display the loading image before the refresh, eg. User clicks, "loading" is shown, page/update panel is refreshed (causing the "loading" to disappear), the new page/content is displayed as normal.
Update 1:
I can't use UpdateProgress because some of the buttons aren't inside UpdatePanels. What I really want to do is to fire a JS as soon as any button/control that will contact the server is clicked. I.e. if the user clicks a dropdown which doesn't contact the server, nothing should happend. But if that dropdown has any connection to the server, a JS should be run.
I understand that this is ASP.NET Ajax and not jQuery Ajax, I only used jQuery as an example. Because I've used a jQuery method before (with jQuery Ajax) to trigger JS before the server call was made. Eg. to lock the element that was clicked or to display a "Loading..." screen.
I could of course add a bit of a JS hack to every page which adds a "onclick" event to every button manually, but I thought it would be better if there was a general solution for this (since I've got lots of pages, each with a few buttons that contact the server on them).
Update 2:
When I think about it, it doesn't necessarily need to be a JS that is triggered. It would be good enough if the page somehow only made sure that the same button wasn't clicked twice. Either by disabeling the button or by adding something in front of it (like a "Loading..." screen).
You can use an UpdateProgress for this to use with update panels, but if you are doing a full page postback (i.e. not ajax) the only loading animation you can have is the browsers own.
UpdateProgress:
<asp:UpdateProgress ID="UpdateProgress1" runat="server">
<ProgressTemplate>
Shiny loading aninmation
</ProgressTemplate>
</asp:UpdateProgress?
Here is how you can do it using jquery:
$(function() {
$('a[href]').on('click', function(e) {
var self = this;
e.preventDefault();
loadAsync($(self).attr('href'));
});
});
function loadAsync(url) {
$('div#result').fadeOut(200, function() {
$('div#loader').fadeIn(200, function() {
$.get(url, function(data) {
$('div#result').html($(data));
}).done(function() {
console.log('done');
}).fail(function() {
$('div#result').html('Error');
}).always(function() {
$('div#loader').fadeOut(200, function() {
$('div#result').fadeIn(200);
});
});
});
});
}
Related
I am using ASP.Net AJAX UpdatePanel to load the right part of the page.
As that part will take some time to load, I would like to load it after the other parts of the page is loaded.
I can use either normal AJAX or ASP.Net AJAX but I chose to use the latter as I want to try it out.
I found out that my UpdatePanel is always loaded.
I want it to be loaded only after the page is ready.
Some says to use the timer, some says to use some javascript.
But I still can't get it done.
So, these are my 2 obstacles, to stop loading when the page starts and to start loading when the page is ready
why don't you enable and disable on page events? for example. try in Page_PreLoad event, set the update panel's enable property to False. While in Page_LoadComplete event, set it back to enabled = true
UpdatePanels use Ajax to update, not on first load.
If you want it to load quickly on first load, avoid any expensive processing, database calls on load. Put them in an
if(IsPostBack)
{
//your long processing
}
Now use an AsyncPostBackTrigger to make your updatePanel postback.
try with this code ( Conditional Mode + Update Method)
<asp:UpdatePanel ID="YourIdPanel" UpdateMode="Conditional" runat="server">
//In order to force loading
YourIdPanel.Update();
<script type="text/javascript">
var currentItemID=$('#<%= labcurrentItemID.ClientID %>').html();
if (currentItemID != null) {
$(document).ready(function () {
$('#main_container').load('/Custom/Going%20Places/PopularRelatedArticle.aspx?currentID=' + currentItemID);
});
}
else {
$(document).ready(function () {
$('#main_container').load('/Custom/Going%20Places/PopularRelatedArticle.aspx?currentID={7F0811A7-D484-4675-8A23-0AEB235B9B5F}');
});
}
</script>
I have a function inside my .aspx.cs code which takes wuite a long time to do the processing until when I want to display a cool loading animation. I looked some of the earlier posts but either these didn't work for me, or were having solution specific to Page loading scenario (not loading a while a function completes).
I guess the right approach would be to fire a Javascript startLoader() function just before the the main function starts (which takes a long time), and then call a stopLoader() from the .aspx.cs itself to stop the loader when the function ends. Any suggestions how to implement this?
Yes, I've done this in ASP.NET Web From (not a ASP.NET MVC solution). You need to provide OnSubmit client side event handler. It basically break down to three parts: Javascript, HTML Div, and one line code behind:
Javscript:
function ShowLoading(e) {
// var divBg = document.createElement('div');
var divBg = document.getElementById('blockScreen');
var divLoad = document.createElement('div');
var img = document.createElement('img');
img.src = 'images/ajax-loader.gif';
divLoad.setAttribute("class", "blockScreenLoader");
divLoad.appendChild(img);
divBg.appendChild(divLoad);
document.getElementById('blockScreen').style.display = 'block';
// These 2 lines cancel form submission, so only use if needed.
//window.event.cancelBubble= true;
//e.stopPropagation();
}
function HideLoading() {
//alert('hideloading');
document.getElementById("form1").onsubmit = null;
document.getElementById('blockScreen').style.display = 'none';
//alert('done');
}
Add following DIV
<div id="blockScreen" class="blockScreen" style="display:none"> </div>
Finally, add the following to Page_Load in code behind.
Page.ClientScript.RegisterOnSubmitStatement(this.GetType(), "submit", "ShowLoading()");
Now, all of your page postbacks are essentially have to call onsubmit event. It will display the animation before the page postback finishes.
if you really want to do, then the only way is webworkers. You've probably heard about them, or if not, i seriously recommend to have a look.
Yes, fire startLoader() on OnCliencClick of your button or whatever element you are using to fire the server-side event and call stopLoader() from the server-side at the end of your process. Something like this:
//rest of the server-side code above ...
Page.ClientScript.RegisterStartupScript(this.GetType(), "someKey", "stopLoader();", true);
If you don't mind that the browser is not responsive in the meantime, the simplest way of doing this is using an animated gif:
Activity indicators
ajaxload.info
webscriptlab
The trick is showing the image when starting your processing, and hiding it when finished. You can show it in an img, and use jQuery or whatever you want to show/hide it.
If you need the browser to keep responsive, use Web Workers. But be aware that some of the older browsers don't support it. See this reference
Hi everyone I have a web form in which I am having a button on clicking which data back up is being taken, I used the following javascript :
<script language="javascript" type="text/javascript">
function showPleaseWait() {
document.getElementById('PleaseWait').style.display = 'block';
}
</script>
<asp:Button ID="btnTakebackup" runat="server" Text="Take Backup" Enabled="true"
onMouseDown="showPleaseWait()" CausesValidation="false" />
<div id="PleaseWait" style="display: none;">"Please Wait Backup in Progress.."</div>
Hi I am using a button to take a back up.
Now I want to show a message in btnTakebackup_Click() event, whether Back up was successful or not.
I used Response.Write("<script>alert('abcd');</script>"); in btnTakebackup_Click() event.
But the problem is that I want to show the page also, which is not showing instead white background is showing.
Thanks in advance...
To show a message box alert should be able to write out a new script to the response stream:
var script =
"<script type=\"javascript\">" +
"alert(\"Backup in progress, don't go!\");" +
"</script>"
Response.Write(script);
However much this is distasteful, I suppose it is sometimes "necessary".
You can add client side event handlers to ASP controls:
How to: Add Client Script Events to ASP.NET Web Server Controls
Cheers.
Do you really want it to be an alert? (You should know that they lock up the whole browser not just the tab your page is on), do your users really need to acknowledge the backup success by clicking ok or just be informed of it?...
I suggest you have a div on the page that says "Backup successful". The visibility of which can be set by a boolean property BackUpSuccess which you can set to true in the code behind you mention.
<div id="backUpSuccess" <%=BackUpSuccess ? "" : "style='display:none;'"%>>
Backup was successfull
</div>
...you can style the div as you like in your .css file to get attention.
If you really do want an alert you could run some JavaScript on page load to check the content of a hidden input that you set server side in similar fashion...but running javascript on page load is tricky...unless your using jQuery and then you will know it's very easy.
From your question, I understood that after clicking on the button, the data back up is happening, but the alert is not displaying as soon as you clicked the button.This is because you are calling the JavaScript in the button click event which will be fired only after all the code in the button click is executed.I suggest you to add a JavaScript function in the .aspx source page it self and call the JavaScript function as shown below:
<script ...>
function xyz()
{
alert('Please Wait');
}
</script>
and in button declaration
<asp:button id='btn_submit' runat="server" OnClientClick="return xyz();" />
I have one GridView which has one CheckBox and three TextBoxes in its template column.
The logic is, when I check the CheckBox, the corresponding TextBoxes should get enabled. If I uncheck the CheckBox, then the corresponding TextBoxes should get disabled. I have written JavaScript for this functionality.
Everything is working fine, but in that page I have one DropDownList too. When I change the DropDownList value, the page gets PostBack and at that time I lost the JavaScript functionality, i.e. the enabled TextBoxes in the GridView gets disabled. How to solve this problem?
After every post back in the update panel you need to reinitialize your javascript, because as you understand the struct of the html has change and javascript runs on the previous one that not exist after the update panel updates. Microsoft gives a functionality to do that as follow.
This is javascript lines.
<script type="text/javascript">
var prm = Sys.WebForms.PageRequestManager.getInstance();
prm.add_initializeRequest(InitializeRequest);
prm.add_endRequest(EndRequest);
function InitializeRequest(sender, args) {
}
function EndRequest(sender, args) {
// here initialize again your javascript
}
</script>
Use the RowCreated event for the ASP Grid to add the client function on the check box, this way the client function will stay on each postback
You must register your javascript at each postback for it to run, by using the ScriptManager.RegisterStartupScript method: here's an example (edited for article in english, sorry :p).
Use auto post back with check box to enable disable text box from server side code. This will update the view state and so it will be maintained on select change. Use these inside UpdatePanel for ajax. Alternatively, you can add drop down into updatepanel as well, so that select change does not affect other page elements.
JavaScript is working on DOM. When page gets PostBack values from ViewState are written to DOM and overwrites your JavaScript changes. You should store state of checkboxes in persistent way ie. jQuery data() or hiddenfield and after PostBack write changes back to DOM.
I encouter some postback issue when using GetPostBackEventReference. Here is the Scenario:
I have a javascript modal popup dialog and got a button in this modal dialog which used to select things (this is NOT an asp:button control)
When this javascript dialog HTML button is clicked, it will call the MS AJAX web service call by the javascript: eval() method. And this MS AJAX web service call is dynamically generated. So the code is like this:
var serviceCall = svcCall + "(" + parameters + ")"; //dynamically generate the MS AJAX web service call here
eval(serviceCall);
//use eval to trigger the MS AJAX web service call
As you may all know, after complete the MS AJAX web service, you can define a callback function to handle the completion:
function OnComplete(result, userContext, methodName) {
//force to call postback manually
eval($(userContext[0]).val());
//close the javascript dialog here
}
As I have mentioned before, the MS AJAX web service call is built dynamically, and when the MS AJAX web service call is construct, it will be passing a userContext which contain the postback value (i.e. "__doPostBack('ctl00$ContentPlaceHolder1$btnSelectUser','')", so when the javascript eval() is called, it simulate a asp:button click postback.
The userContext[0] basically holding a asp:hidden field's ClientID, and the hidden field's value is set during the Page_Load event:
protected void Page_Load(object sender, EventArgs e)
{
btnSelectUser.ValidationGroup = "popupSelect";
btnSelectUser.CausesValidation = false;
this.hdnBtnPostback.Value = Page.ClientScript.GetPostBackEventReference(btnSelectUser, string.Empty, false);
}
As you can see, this is how I bound the asp:button (i.e. btnSelectUser) 's Click Event to the asp:hiddenfield using the GetPostBackEventReference, and set the registerForEventValidation argument to false. I have also tried to use different ValidationGroup and set the CausesValidation to false, but no hope. :(
In summarize, I bound the asp:button's Click PostBackEventReference(i.e. __doPostback(....)) to the asp:hidden field's Value attribute, and using javascript eval() to eval this hidden field's value in order to manually trigger postback.
p.s. the btnSelectUser is an asp:button control and used to call out the javascript modal dialog.
Ok, here is the Problem:
In the same page, there is some asp:validator, e.g. and , and of coz, when the page run into error, this validator and callout will display to the user. e.g. When the user didn't fill in anything and submit the form, the ValidatorCalloutExtender will display a ballon and tell the user. Imagine one of this ballon/validatorCalloutExtender come out and on top of your screen at the moment.
Then you click the btnSelectUser (asp:button) to show the javascript modal dialog, and in the dialog, you Add some users, and once you hit the SELECT button inside this modal dialog, a MS AJAX web service is trigger as mentioned above, and once this web service is complete, it eval() the asp:hidden field's value (i.e. __doPostback(...))......and do the postback manually.
However, because of the validatorCalloutExtender ballon has display, it somehow cannot trigger the postback in this way, but when I close the ballon/validatorCalloutExtender, the manual postback using eval() is just working fine. Even more strange is that, when the ballon is displayed, the first time I click the SELECT button inside this modal dialog it doesn't fire the postback, however, if I do the same thing again (i.e. open up the javascript dialog, and choose some users, then click the SELECT button again). It able to do the manual postback....and I don't understand why the first time doesn't work.
This has really drive me crazy, hope anyone here can help, would be really appreciate. Thank you so much folks. :)
Have a nice day. Looking to heard from you all shortly.
When you call __doPostBack(eventTarget, eventArgument) a form submission is triggered:
This from post will proceed if WebForm_OnSubmit(); return true.
WebForm_OnSubmit result depends on ValidatorOnSubmit result, which in turn depends on
ValidatorCommonOnSubmit result if Page_ValidationActive == true.
Now if you are still with me, as in the function below:
function ValidatorCommonOnSubmit() {
Page_InvalidControlToBeFocused = null;
var result = !Page_BlockSubmit;
if ((typeof(window.event) != "undefined") && (window.event != null)) {
window.event.returnValue = result;
}
Page_BlockSubmit = false;
return result;
}
The result of ValidatorCommonOnSubmit depends on Page_BlockSubmit, so the only thing to block your postback is Page_BlockSubmit == true, it has nothing to do with validation callouts.
I was unable to simulate your case, but if you could post a full code sample it will help me track down the issue.