Sys.WebForms.PageRequestManager endRequest Event raised only when an error - asp.net

Question

I am using an updatepanel and I'd like to use the Sys.WebForms.PageRequestManager endRequest event to display a success message. But I can only get this event to fire when I generate an error in my procedure. My understanding is that it should fire all the time. What am I missing?

Answer 1

So, you don't give much context here.
but, lets use a update panel, drop in a simple button.
On button click, we will display a please wait.....
For code behind on button click, we just do a "sleep" for 4 seconds to fake a long running process.
When done, of course the post-back will automatic hide the please wait message, and then we have some javascript code run by using "end request".
so, first up, our markup in the UP, and a simple please wait....
(we don't need a UP for that simple please wait processing message, but lets just use a UP for this).
So, this:
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<h3>Start the Big Process</h3>
<asp:Button ID="cmdStart" runat="server"
Text="Start Process" CssClass="btn"
ClientIDMode="Static"
OnClick="cmdStart_Click" />
<asp:UpdateProgress ID="UpdateProgress1" runat="server">
<ProgressTemplate>
<img src="Content/wait2.gif" width="64" />
Update in progress...
</ProgressTemplate>
</asp:UpdateProgress>
</ContentTemplate>
</asp:UpdatePanel>
So, how the "Progress Template works", is that area and markup is displayed DURING the post back. So, very handy.
So, say the code behind is this:
protected void cmdStart_Click(object sender, EventArgs e)
{
// fake 4 seconds long running
System.Threading.Thread.Sleep(4000);
}
So, when we run, we get/see this effect:
Now, of course we want a message, or at the very least to run some client side code AFTER the post-back (processing) is done.
Well, we can adop, use the very "long time" approach of simple using a register client script at the end of the code. And as such, no update panel event is required.
So, say after done, we want a client side alert(), or even better, say a toast message (any kind of client side js code is the goal here).
So, we could say do this:
protected void cmdStart_Click(object sender, EventArgs e)
{
// fake 4 seconds long running
System.Threading.Thread.Sleep(4000);
MyToast(this.Page, cmdStart.ClientID, "Processing Complete",
#"All steps for project<br/>are now complete", "6000");
}
void MyToast(Page mypage, string ctrlBeside,
string Heading, string strMessage,
string strDelay = "3000")
{
string strScript =
#"toastcall('#ctrlBeside','#Heading','#Text','#strDelay');";
strScript = strScript.Replace("#ctrlBeside", ctrlBeside);
strScript = strScript.Replace("#Heading", Heading);
strScript = strScript.Replace("#Text", strMessage);
strScript = strScript.Replace("#strDelay", strDelay);
ScriptManager.RegisterStartupScript(mypage, mypage.GetType(), "mytoast", strScript, true);
}
Now, I just have a toast message "helper" in above, and all it does is setup the js code, and inject (register). Do note that in place of Page.ClientScript.RegisterStartupScript, we used ScriptManger to register (we need to do this for update panels - other than that - same functionally).
And of course, I do assume in place of a simple alert(), that I have jQuery.toast installed.
So, I have this client side js code in that page:
function toastcall(sControl, sHeading, sMsg, sTime) {
var btn = $('#' + sControl)
var btnpos = btn.position()
$.toast({
heading: sHeading,
text: sMsg,
position: {top: (btnpos.top + btn.height()), left: btnpos.left + btn.width()},
icon: 'info',
hideAfter: sTime,
allowToastClose: false,
loader: false,
showHideTransition: 'slide'
});
}
And now we get this effect:
So far we really don't need that event, since the "last line" of the code behind is free like "any" and "all" code behind to inject some js script to run.
And if you want a another button on the page OUTSITE of UP to trigger that up?
Then just use a client side button, and use a "click" of a button inside of the UP.
Say like this:
<asp:Button ID="Button2" runat="server" Text="client side button - trigger update panel"
OnClientClick="$('#cmdStart').click();return false"
/>
So, the above will run the button inside of the UP, and not a full page post back.
However, just place that 2nd button in another UP, and that click will then ALWAYS load + post BOTH UP's. (in fact all on the given page will ALWAYS be posted back as a whole group of UP's). If you don't want all UP's posted back to the server, then you have to add this to the UP.
UpdateMode="Conditional"
So, keep in mind that multiple UP's all post back by default unless you add above. (of course that ONLY applies to a UP post-back, since with a regular button and post-back outside of UP, then you have a regular plain jane post-back).
So, do keep in mind that UP is in fact a post-back! - or better stated what we call a "partial page post back". And not that when using a UP, even the page load event fires EACH time.
So, a UP does not 100% eliminate a post-back, despite it "appearing" to not have a post-back. A page life cycle and "round trip" does occur, but only the "things" inside of the UP are posted back.
Ok, last but not least?
The question is how to use end request event?
that event is for CLIENT SIDE code, not server side.
So, in place of that register script at the end of the server side code (in update panel), we could have the UP panel ALWAYS call some client side code, and we thus eliminate the requirement to "register" some client side js code to run.
As I stated, the "use case" for this is not all that great, since we have the ability to register any script in the server side code anyway.
however, lets remove the register script code, and use the "end request" event of the update panel.
So, we do it this way:
<script>
var prm = Sys.WebForms.PageRequestManager.getInstance();
prm.add_endRequest(mytoastmsg);
function mytoastmsg() {
btnID = $('#cmdStart').attr("id")
toastcall(btnID, "Processing Complete",
"All steps for project<br/>are now complete", "6000")
}
function toastcall(sControl, sHeading, sMsg, sTime) {
var btn = $('#' + sControl)
var btnpos = btn.position()
$.toast({
heading: sHeading,
text: sMsg,
position: {top: (btnpos.top + btn.height()), left: btnpos.left + btn.width()},
icon: 'info',
hideAfter: sTime,
allowToastClose: false,
loader: false,
showHideTransition: 'slide'
});
}
</script>
So, note the add_endRequest - that sets up the "end request" code client side. So, now for any and all "end" of the UP, that one js code stub will run.
so, our button in UP becomes this:
protected void cmdStart_Click(object sender, EventArgs e)
{
// fake 4 seconds long running
System.Threading.Thread.Sleep(4000);
//MyToast(this.Page, cmdStart.ClientID, "Processing Complete",
// #"All steps for project<br/>are now complete", "6000");
}
So, for testing, we just commented out the final script register, since now, the "end request" setup will fire + trigger the client side js code ALWAYS at the end of the post back for the UP.
the effect is 100% the same as the register script example.