asp.net external JavaScript file doesn't find Control.ClientID - asp.net

On load I'm both calling a JavaScript setTimeout() function that will hide a .NET Panel control, and hiding it in the code behind on first load. Clicking the save button will set the Panel to visible then reload the page at which point a setTimeout() function is called... so basically you click save, and see a panel with "Details Saved" for three seconds, at which point it disappears.
The problem is the external JavaScript file can't find _pDivAlert.ClientID (I've debugged and it returns null). It only works when the code is in a tag in the .aspx page. Any suggestions as to how I can either pass the client ID to the HideControl() function or find the ClientID from the external JS file?
Here's my code, any suggestions?
<script language="javascript" src="Forms.js" type="text/javascript"></script>
<body onload="ToggleAlert()">
<form id="form1" runat="server">
<script type="text/javascript">
//alert the user that the details were saved
function HideControl() {
var control = document.getElementById('<%=_pDivAlert.ClientID %>');
if(control != null)
control.style.display = 'none';
}
function ToggleAlert() {
setTimeout("HideControl()", 3000);
}
</script>
I've also tried sending the ClientID within the ToggleAlert() call, but that didn't work:
<body onload="ToggleAlert('<%=_pDivAlert.ClientID %>')">
External JS:
function HideControl(_c) {
var control = _c;
if (control != null)
control.style.display = 'none';
}
function ToggleAlert(_c) {
setTimeout("HideControl(_c)", 3000);
}

can you show your markup with the panel and the codebehind where you hide it?
there's a difference between setting the Visible property to false and setting the style display attribute to none- the first will not render the element at all, meaning there isn't anything rendered with the id you're looking for.
edit: it's probably because of the way you're calling HideControl in the timeout- this should be a function instead of a string.
try doing
function ToggleAlert(_c) {
setTimeout(
function () {
HideControl(_c);
}, 3000);
}
just for clarity, when you pass a string to setTimeout, it's evaluated and then run. the code chunk that eval produces will run in a different scope than your ToggleAlert method, and so _c won't be available at that time.
edit: you also need to actually get a reference to the control. you're passing the id string to ToggleAlert, which relays it to HideControl, which is expecting an object not a string.
function HideControl(_c) { // _c is the id of the element
var control = document.getElementById(_c);
if (control != null)
control.style.display = 'none';
}

Related

Access variablea of javascript in .aspx.vb file

I want to access variables defined in Javascript in.aspx file to .aspx.vb file
How can i access variables in .aspx.vb file?
<script type="text/javascript" language="javascript">
var c=0;
var m=0;
var h=0;
var t;
var timer_is_on=0;
function startTMR()
{
document.getElementById('TimeLable').value=h+":"+m+":"+c;
c=c+1;
if(c==60)
{
c=0;
m=m+1;
if(m==60)
{
m=0;
h=h+1;
}
}
t=setTimeout("startTMR()",1000);
}
function doTimer()
{
if (!timer_is_on)
{
timer_is_on=1;
startTMR();
}
}
This is simple javascript I'm using in my .aspx page
now i want to access the variable h m and c in .aspx.vb page how to do that?
You'll need to save that javascript variable into a hidden input, which will post with your form when you do a postback. You'll be able to access the value via:
string value = Request.Form["hiddenName"];
Assuming you declare your hidden input like this:
<input type="hidden" id="hiddenValue" name="hiddenName" />
You can set this value like this with native JavaScript:
document.getElementById("hiddenValue").value = "12";
or with jQuery like this:
$("#hiddenValue").val("12");
If you'd like to make sure this hidden input is automatically saved to the JavaScript variable x before you post back, you could do the following with jQuery
$("#form1").submit(function () {
$("#hiddenValue").val(x);
});
Or this with native JavaScript:
document.getElementById("form1").addEventListener("submit", function () {
document.getElementById("hiddenValue").value = x;
});
If you're not using jQuery, and you opt for this native option, just make sure you put the script at the bottom of the body section; do not put this script in the head, since the dom is not formed yet, and you will get a null error.
And obviously this all assumes your form element looks like this:
<form id="form1" runat="server">
if yours has a different id, then adjust accordingly.

sender._postBackSettings.sourceElement is undefined

This is what I'm trying to do -
Using jQuery when the document is ready and if the page is not postback I issue a manual postback for an updatepanel to retrieve data from a database.
While the updatepanel is getting the data I present an updateprogress which I hide when the specific updatepanel finishes. I also want to "BLOCK" the screen from any interaction. After the data is loaded I have additional buttons on the form and I want to block everything in case of any partial-postback.
Here is the code:
$(document).ready(function ()
{
if(<% =(Not Page.isPostBack).ToString().ToLower() %>)
{
__doPostBack('upShipping');
}
}
function pageLoad() {
var prm = Sys.WebForms.PageRequestManager.getInstance();
prm.add_beginRequest(BeginRequestHandler);
prm.add_endRequest(EndRequestHandler);
}
function BeginRequestHandler(sender, args)
{
$('.blur').css("display", "block");
if (args._postBackElement.id == 'upShipping') {
$get('divCalculating').className = 'Show';
}
}
function EndRequestHandler(sender, args)
{
$('.blur').css("display", "none");
if (sender._postBackSettings.sourceElement.id == 'upShipping')
{
$get('divCalculating').className = 'Hidden';
}
}
If I do not "CLICK" on the screen everything works great. But if I just click anywhere on the screen while the updatepanel updates the "EndRequestHandler" doesn't fire and I'm stuck with the loading gif and blocked screen.
I get the following error in the error console of the browser: sender._postBackSettings.sourceElement is undefined
Any ideas?
Thanks!
Nick
For some reason sender._postBackSettings.sourceElement kept coming back as NULL in the EndRequestHandler.
I defined a global var, assigned it a value at the BeginRequestHandler and checked its value instead in the EndRequestHandler.
This solved the problem.

How to get the id of Updatepanel which is about to start a postback

I need to get the id of the panel that is about to start a postback, so I have a generic way to block ui on this panel.
So far I have this function:
function BeginRequestHandler(sender, args) {
$('#' + args.get_updatePanelsToUpdate()[0]).block({ message: null });
}
attached like this:
Sys.WebForms.PageRequestManager.getInstance().add_beginRequest(BeginRequestHandler);
this works pretty well to get the id if control that causes partial postback is inside update panel, but if it is outside (using a trigger), args.get_updatePanelsToUpdate() is always null
I've seen this answer, but it wont work forme because function is fired after partial postback is complete, I need it before..
Thank you
So here's what I did:
created 2 functions to block (on partial postback begin) and unblock (on partial postback end):
function BeginRequestHandler(sender, args) {
$('#' +sender._postBackSettings.panelsToUpdate[0].ReplaceAll('$', '_')).block({ message: 'loading...' });
}
function EndRequestHandler(sender, args) {
$('#' + sender._postBackSettings.panelsToUpdate[0].ReplaceAll('$', '_')).unblock();
}
Registered above functions on my page right after my script manager:
<script type="text/javascript">
Sys.WebForms.PageRequestManager.getInstance().add_endRequest(EndRequestHandler);
Sys.WebForms.PageRequestManager.getInstance().add_beginRequest(BeginRequestHandler);
</script>
Some conditions:
I'm using jquery UI block plugin but you should use what better fits your needs.
You update panels should have ClientIDMode="AutoID" if your using .NET 4.0 +
I used the following helper function cause js doesn't make a real replace all and to deal with asp net autoID's:
String.prototype.ReplaceAll = function (stringToFind, stringToReplace) {
var temp = this;
var index = temp.indexOf(stringToFind);
while (index != -1) {
temp = temp.replace(stringToFind, stringToReplace);
index = temp.indexOf(stringToFind);
}
return temp;
}
If you just want to disable (or animate in some other way) the UpdatePanel, why not just use UpdatePanelAnimation? It provides you with the following hooks (not sure if that's the right word):
OnUpdating - Generic animation played as when any UpdatePanel begins
updating
OnUpdated - Generic animation played after the UpdatePanel
has finished updating (but only if the UpdatePanel was changed)

C# .NET and Javascript Confirm

I have a C# ASP.NET web page with an xml file upload form. When the user clicks 'upload', a javascript confirm alert will pop up asking the user, "is this file correct?". The confirm alert will only activate if the file name does not contain a value from one of the other form fields.
What is the best way to combine the use of a C# ASP.NET form and a javascript confirm alert that is activated if the name of a file being uploaded does not meet certain criteria?
There's not much you need to do with C# for this page, it sounds like most of this will be done on the client side.
Add the fileupload control and a button to your .aspx form. Set the Button's OnClientClick property to something like
OnClientClick = "return myFunction()"
and then write a javascript function like:
function myFunction()
{
// Check other text values here
if (needToConfirm){
return confirm('Are you sure you want to upload?');
}
else return true;
}
Make sure "myFunction()" returns false if you wish to cancel the postback (i.e. the user clicked "no" in the confirm dialog). This will cancel the postback if they click "No".
I suppose you are putting value of valid string in a hidden field (you haven't mentioned). Implement OnClientClick for Upload button:
<asp:button .... OnClientClick="return confirmFileName();"/>
<script type="text/javascript">
function confirmFileName()
{
var f = $("#<%= file1.ClientID %>").val();
var s=$("#<%= hidden1.ClientID %>").attr("value");
if (f.indexOf(s) == -1) {
if (!confirm("Is this correct file?")) {
$("#<%=file1.ClientID %>").focus();
return false;
}
}
return true;
}
</script>
EDIT:- Regarding <%= file1.ClientID %>.
This will be replaced by the client side ID of the file upload control like ctl00$ctl00$cphContentPanel$file1. It puts the script on steroids with respect to using something like $("input[id$='file1']"). For more information please see Dave Wards' post.
window.onload = function() {
document.forms[0].onsubmit = function() {
var el = document.getElementById("FileUpload1");
var fileName = el.value;
if(fileName.indexOf("WHATEVER_VALUE") == -1) {
if(!confirm("Is the file correct?")) {
el.focus();
return false;
}
}
return true;
}
}
I had problems implementing this kind of thing to work in both IE and FireFox because of the way events work in those browsers. When I got it to work in one of them, the other would still cause a postback even if I cancelled out.
Here's what we have in our code (the browser test was stolen from elsewhere).
if (!window.confirm("Are you sure?"))
{
if (/MSIE (\d+\.\d+);/.test(navigator.userAgent))
window.event.returnValue = false;
else
e.preventDefault();
}
In addition to using client side validation, you should also add a CustomValidator to provide validation on the server side. You cannot trust that the user has Javascript turned on, or that the user has not bypassed your Javascript checks.

ASP.NET: Scroll to control

I've got a particularly large form in an page. When the form is validated and a field is invalid, I want to scroll the window to that control. Calling the control's Focus() doesn't seem to do this. I've found a JavaScript workaround to scroll the window to the control, but is there anything built into ASP.NET?
Page.MaintainScrollPositionOnPostBack = False
Page.SetFocus(txtManagerName)
Are you using a Validation Summary on your page?
If so, ASP.NET renders some javascript to automatically scroll to the top of the page which may well override the automatic behaviour of the client side validation to focus the last invalid control.
Also, have you turned client side validation off?
If you take a look at the javascript generated by the client side validation you should see methods like this:
function ValidatorValidate(val, validationGroup, event) {
val.isvalid = true;
if ((typeof(val.enabled) == "undefined" || val.enabled != false) &&
IsValidationGroupMatch(val, validationGroup)) {
if (typeof(val.evaluationfunction) == "function") {
val.isvalid = val.evaluationfunction(val);
if (!val.isvalid && Page_InvalidControlToBeFocused == null &&
typeof(val.focusOnError) == "string" && val.focusOnError == "t") {
ValidatorSetFocus(val, event);
}
}
}
ValidatorUpdateDisplay(val);
}
Note the call to ValidatorSetFocus, which is a rather long method that attempts to set the focus to the control in question, or if you have multiple errors, to the last control that was validated, using (eventually) the following lines:
if (typeof(ctrl.focus) != "undefined" && ctrl.focus != null) {
ctrl.focus();
Page_InvalidControlToBeFocused = ctrl;
}
To get this behaviour to work, you would ideally need to ensure that all your validators are set to be client-side - server side validators will obviously require a postback, and that might affect things (i.e. lose focus/position) - and setting MaintainScrollPositionOnPostBack to true would probably cause the page to reload to the submit button, rather than the invalid form element.
Using the server side .Focus method will cause ASP.NET to render out some javascript "on the page load" (i.e. near the bottom of the page) but this could be being overriden by one of the other mechanisms dicussed above.
SO I believe the problem is because I was trying to focus on HtmlGenericControls instead of WebControls.
I just ended up doing a workaround based off of:
http://ryanfarley.com/blog/archive/2004/12/21/1325.aspx
http://www.codeproject.com/KB/aspnet/ViewControl.aspx
...in the interest of time.
public static void ScrollTo(this HtmlGenericControl control)
{
control.Page.RegisterClientScriptBlock("ScrollTo", string.Format(#"
<script type='text/javascript'>
$(document).ready(function() {{
var element = document.getElementById('{0}');
element.scrollIntoView();
element.focus();
}});
</script>
", control.ClientID));
}
Usage:
if (!this.PropertyForm.Validate())
{
this.PropertyForm.ErrorMessage.ScrollTo();
failed = true;
}
(Although it appears Page.RegisterClientScriptBlock() is deprecated for Page.ClientScript.RegisterClientScriptBlock()).
Adding MaintainScrollPositionOnPostback is the closest that ASP.NET has built in, but won't necessarily jump to the invalid field(s).
<%# Page MaintainScrollPositionOnPostback="true" %>
Very simple solution is to set the SetFocusOnError property of the RequiredFieldValidator (or whichever validator control you are using) to true
Are you sure Focus() won't do what you're describing? Under the hood, it is essentially doing the "JavaScript workaround" - it writes some JS to the page which calls focus() on the control with the matching ID:
Whichever control had Focus() called last before the page finishes processing writes this to the page:
<script type="text/javascript">
//<![CDATA[
WebForm_AutoFocus('txtFocus2');//]]>
</script>
Please insert these into your OnClick event
Page.MaintainScrollPositionOnPostBack = false;
Page.SetFocus("cliendID");
// or
Page.setFocus(control);
You should looks into jQuery and the ScrollTo plugin
http://demos.flesler.com/jquery/scrollTo/
I've achieved something similar using basic HTML fragments. You just leave an element with a known ID:
<span id="CONTROL-ID"></span>
And then either via script, on on the server side change the url:
window.location += "#CONTROL-ID";
In the first case the page won't reload, it will just scroll down to the control.
Paste the following Javascript:
function ScrollToFirstError() {
Page_ClientValidate();
if (Page_IsValid == false) {
var topMostValidator;
var lastOffsetTop;
for (var i = 0; i < Page_Validators.length; i++) {
var vld = Page_Validators[i];
if (vld.isvalid == false) {
if (PageOffset(vld) < lastOffsetTop || lastOffsetTop == undefined) {
topMostValidator = vld;
lastOffsetTop = vld.offsetTop;
}
}
}
topMostValidator.scrollIntoView();
}
return Page_IsValid;
}
function PageOffset(theElement) {
var selectedPosY = 0;
while (theElement != null) {
selectedPosY += theElement.offsetTop;
theElement = theElement.offsetParent;
}
return selectedPosY;
}
Then call ScrollToFirstError() in your OnClientClick of the button that is saving, make sure the button has CausesValidation=true as well.
There you have it.

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