C#: Preventing AutoPostBack according to a confirmation dialog
I want to show a confirmation dialog when a specific value is selected in an asp:DropDownList. If the confirmation dialog returns false (开发者_开发百科cancel) then I want to prevent the AutoPostBack.
<asp:DropDownList id="theDropDownID" onchange="foo()"></asp:DropDownList>
However, it ignores the returned value from foo() and actually does the postback.
The generated code of the onchange event is:foo(); setTimeout("__doPostBack('theDropDownID','')", 0);
so basically controlling the setTimeout that the .net adds, will do the job.
Any idea how?
Thanks!Either
onchange="return foo();"
function foo() {
//do whatever
return false;
}
Or use the following jQuery
$(function () { //equivallent to: $(document).ready(function() {
$('#theDropDownID').removeAttr('onchange');
$('#theDropDownID').change(function(e) {
e.preventDefault();
if (confirm("do postback?")) {
setTimeout('__doPostBack(\'theDropDownID\',\'\')', 0);
}
});
});
I prefer the second approach because it is unobtrusive javascript: all of the behaviour is together and there is no inline javascript at all.
Try setting the onchange value to:
onchange="return foo();"
that should do the trick normally.
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