DropDownList的不触发onbeforeunload时的AutoPostBack =＆QUOT;真＆QUOT; [英] DropDownList not firing onbeforeunload when AutoPostBack="True"
问题描述
我已经实现了使用在这些网页上描述的技术是未保存的更改警告：
http://stackoverflow.com/questions/140460
http://kenbrowning.blogspot.com/2009/ 01 /使用-的jQuery到standardize.html
这工作得很好，除了在页面上一个DropDownList。它的的AutoPostBack，我想onbeforeunload火因未保存的更改将丢失，但它不工作。它应该是提高onbeforeunload事件？我能以某种方式使其引发事件？
编辑：
将DropDownList是一个UpdatePanel里面，所以这意味着它不卸载页面，这将是为什么onbeforeunload不被触发。有没有什么办法可以编程触发事件？还是我必须推出自己的仿制确认对话框？
EDIT2
我现在有一个解决方案，从一个UpdatePanel添加对话框异步回发。我已经编辑原始脚本，将调用在我的解决方案描述setConfirmAsyncPostBack（）。
下面是我的javascript：
/ ****脚本来警告未保存的更改用户**** ///http://stackoverflow.com/questions/140460
//http://jonstjohn.com/node/23//激活确认消息onbeforeunload。
功能setConfirmUnload（上）{ setConfirmAsyncPostBack（）; 如果（上）{
removeCheckFromNoWarnClasses（）;
fixIEonBeforeUnload（）;
window.onbeforeunload = unloadMessage
返回;
} window.onbeforeunload = NULL
}功能unloadMessage（）{ 返回你有未保存的更改。';
}// JavaScript的移动从HREF到的onclick至prevent IE提高onbeforeunload unecessarily
//http://kenbrowning.blogspot.com/2009/01/using-jquery-to-standardize.html
功能fixIEonBeforeUnload（）{ 如果（！$。browser.msie）
返回;
$（'一个'）。过滤（功能（）{
返回（/^javascript\\:/i).test($(this).attr('href'））;
}）。每个（函数（）{
VAR hrefscript = $（本）.attr（'href属性）;
hrefscript = hrefscript.substr（11）;
$（本）。数据（hrefscript'，hrefscript）;
}）。点击（函数（）{
VAR hrefscript = $（本）。数据（hrefscript'）;
的eval（hrefscript）;
返回false;
}）ATTR（'的href'，'＃'）;
}//移除保存按钮，链接等，已经可以得到无警告或无警告 - 验证CSS类的警告
//无警告 - 验证的输入/链接将仅删除验证成功后警告
//使用无警告，校验类上的按钮，导致验证/链接。
//使用无警告级上有控制的CausesValidation =假（例如一个另存为草稿按钮）。
功能removeCheckFromNoWarnClasses（）{ $（'。没有警告-验证'）。点击（函数（）{
如果（Page_ClientValidate == NULL || Page_ClientValidate（））{
setConfirmUnload（假）;
}
}）; $（'没有警告'）。点击（函数（）{
setConfirmUnload（假）;
}）;
}//添加客户端事件的所有输入控件在确认onbeforeunload切换
功能enableUnsavedChangesWarning（）{ $（'：输入'）一（'变'，函数（）{。
window.onbeforeunload =功能（）{
返回你有未保存的更改。';
}
}）; removeCheckFromNoWarnClasses（）;
}
在我的ASP.NET页面，当用户进行了更改：
如果（改变）
{
...
//确认卸载，如果有未保存的更改。
//注意我们也有叫fixIEonBeforeUnload（）来修复链接，在网页加载中完成的，包括那些回调期间呈现链接
ScriptManager.RegisterStartupScript（页，的GetType（），unsavedchanges，setConfirmUnload（真）;，真）;
}
其他
...
另请参阅<一个href=\"http://stackoverflow.com/questions/3298140/how-to-$p$pvent-autopostback-when-dropdownlist-is-selected-using-jquery/3299334#3299334\">http://stackoverflow.com/questions/3298140/how-to-$p$pvent-autopostback-when-dropdownlist-is-selected-using-jquery/3299334#3299334
//http://msdn.microsoft.com/en-us/magazine/cc163413.aspx
//http://stackoverflow.com/questions/2424327/$p$pvent-asp-net-dopostback-from-jquery-submit-within-updatepanel
//添加事件处理函数时异步回发是由一个UpdatePanel初始化确认未保存的更改
功能setConfirmAsyncPostBack（）{ 如果（typeof运算（Sys.WebForms）===未定义|| typeof运算（Sys.WebForms.PageRequestManager）===未定义）
返回; 变种PRM = Sys.WebForms.PageRequestManager.getInstance（）;
prm.add_initializeRequest（confirmAsyncPostBack）;
}//事件处理异步回发，如果他们不确认，确认未保存的更改，取消回发
//添加的确认有一个CSS类元素的警告
功能confirmAsyncPostBack（发件人，参数）{
如果（window.onbeforeunload = NULL＆放大器;！＆安培; args.get_postBackElement（）类名==警告＆放大器;＆安培;！unloadConfirmed（））
args.set_cancel（真）;
}//显示模仿由onbeforeunload显示的对话框确认对话框
功能unloadConfirmed（）{ VAR确认=确认（你确定要导航离开此页面吗？\\ n \\ n+ unloadMessage（）+\\ n \\ n preSS确定继续或取消停留在当前页面。 ）;
如果（确认）
window.onbeforeunload = NULL;
返回确认;
}
I have implemented an "unsaved changes" warning using techniques described on these pages:
http://stackoverflow.com/questions/140460
http://kenbrowning.blogspot.com/2009/01/using-jquery-to-standardize.html
This works well except for a DropDownList on the page. It does an AutoPostBack, and I want onbeforeunload to fire because unsaved changes will be lost, but it isn't working. Should it be raising the onbeforeunload event? Can I somehow make it raise the event?
Edit: The DropDownList is inside an UpdatePanel, so that means it isn't unloading the page and that would be why onbeforeunload isn't being triggered. Is there any way I can trigger the event programmatically? Or do I have to roll my own imitation Confirm dialog?
Edit2 I now have a solution that adds the dialog to asynchronous postbacks from an UpdatePanel. I have edited the original script, adding the call to setConfirmAsyncPostBack() as described in my solution.
Here is my javascript:
/****Scripts to warn user of unsaved changes****/
//http://stackoverflow.com/questions/140460
//http://jonstjohn.com/node/23
//Activates the confirm message onbeforeunload.
function setConfirmUnload(on) {
setConfirmAsyncPostBack();
if (on) {
removeCheckFromNoWarnClasses();
fixIEonBeforeUnload();
window.onbeforeunload = unloadMessage
return;
}
window.onbeforeunload = null
}
function unloadMessage() {
return 'You have unsaved changes.';
}
//Moves javascript from href to onclick to prevent IE raising onbeforeunload unecessarily
//http://kenbrowning.blogspot.com/2009/01/using-jquery-to-standardize.html
function fixIEonBeforeUnload() {
if (!$.browser.msie)
return;
$('a').filter(function() {
return (/^javascript\:/i).test($(this).attr('href'));
}).each(function() {
var hrefscript = $(this).attr('href');
hrefscript = hrefscript.substr(11);
$(this).data('hrefscript', hrefscript);
}).click(function() {
var hrefscript = $(this).data('hrefscript');
eval(hrefscript);
return false;
}).attr('href', '#');
}
//Removes warnings from Save buttons, links, etc, that have been can be given "no-warn" or "no-warn-validate" css class
//"no-warn-validate" inputs/links will only remove warning after successful validation
//use the no-warn-validate class on buttons/links that cause validation.
//use the no-warn class on controls that have CausesValidation=false (e.g. a "Save as Draft" button).
function removeCheckFromNoWarnClasses() {
$('.no-warn-validate').click(function() {
if (Page_ClientValidate == null || Page_ClientValidate()) {
setConfirmUnload(false);
}
});
$('.no-warn').click(function() {
setConfirmUnload(false);
});
}
//Adds client side events to all input controls to switch on confirmation onbeforeunload
function enableUnsavedChangesWarning() {
$(':input').one('change', function() {
window.onbeforeunload = function() {
return 'You have unsaved changes.';
}
});
removeCheckFromNoWarnClasses();
}
And in my ASP.NET page, when the user makes a change:
if (changed)
{
...
//Confirm unload if there are unsaved changes.
//NB we also have to call fixIEonBeforeUnload() to fix links, done in in page load to include links that are rendered during callbacks
ScriptManager.RegisterStartupScript(Page, GetType(), "unsavedchanges", "setConfirmUnload(true);", true);
}
else
...
//http://msdn.microsoft.com/en-us/magazine/cc163413.aspx
//http://stackoverflow.com/questions/2424327/prevent-asp-net-dopostback-from-jquery-submit-within-updatepanel
//Adds an event handler to confirm unsaved changes when an asynchronous postback is initialised by an UpdatePanel
function setConfirmAsyncPostBack() {
if (typeof (Sys.WebForms) === "undefined" || typeof (Sys.WebForms.PageRequestManager) === "undefined")
return;
var prm = Sys.WebForms.PageRequestManager.getInstance();
prm.add_initializeRequest(confirmAsyncPostBack);
}
//An event handler for asynchronous postbacks that confirms unsaved changes, cancelling the postback if they are not confirmed
//Adds the confirmation to elements that have a css class of "warn"
function confirmAsyncPostBack(sender, args) {
if (window.onbeforeunload != null && args.get_postBackElement().className == "warn" && !unloadConfirmed())
args.set_cancel(true);
}
//Displays a confirmation dialog that imitates the dialog displayed by onbeforeunload
function unloadConfirmed() {
var confirmed = confirm("Are you sure you want to navigate away from this page?\n\n" + unloadMessage() + "\n\nPress OK to continue or Cancel to stay on the current page.");
if (confirmed)
window.onbeforeunload = null;
return confirmed;
}
这篇关于DropDownList的不触发onbeforeunload时的AutoPostBack =＆QUOT;真＆QUOT;的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
