Commented Issue: Wrong eventArgs for PageRequestManager.add_beginRequest if using LinkButtons [27272]

I encountered a bug within the PageRequestManager when using LinkButtons for async/ajax Updates.

If you add a listener to the Sys.WebForms.PageRequestManager.add_beginRequest event and raise an async postback using a LinkButton, the eventArgs will be empty (no postBackElement or panelsToUpdate will be set).

An example can be found in this Forum Post: http://forums.asp.net/t/1841094.aspx/1

The bug is in the _doPostBack Method of the PageRequestManager.

Checkout the _doPostBack method in http://ajaxcontroltoolkit.codeplex.com/SourceControl/changeset/view/1014bf767f65#Client%2fMicrosoftAjax%2fExtensions%2fSys%2fWebForms%2fPageRequestManager.js

There is this code piece:

var mpUniqueID = this._masterPageUniqueID;
// If it's not a cross-page post, see if we can find the DOM element that caused the postback
var clientID = this._uniqueIDToClientID(eventTarget);
var postBackElement = document.getElementById(clientID);
if (!postBackElement && mpUniqueID) {
if (clientID.indexOf(mpUniqueID + "$") === 0) {
// With ClientIDMode=Predictable, the MasterPageID is missing from the beginning
// of the client ID.
postBackElement = document.getElementById(clientID.substr(mpUniqueID.length + 1));
}
}

But the check in the inner if-condition is wrong! The clientID will never contain the masterPageUniqueID since it is a clientID (seperated with underscores) converted from a uniqueID (seperated with dollars). The check need to be done on the uniqueID which is stored in the eventTarget.

var mpUniqueID = this._masterPageUniqueID;
// If it's not a cross-page post, see if we can find the DOM element that caused the postback
var clientID = this._uniqueIDToClientID(eventTarget);
var postBackElement = document.getElementById(clientID);
if (!postBackElement && mpUniqueID) {
if (eventTarget.indexOf(mpUniqueID + "$") === 0) {
// With ClientIDMode=Predictable, the MasterPageID is missing from the beginning
// of the client ID.
clientID = eventTarget.substr(mpUniqueID.length + 1)
postBackElement = document.getElementById(clientID);
}
}

After this fix the postBackElement can be found and the eventArgs contain the valid data.
Comments: PageRequestManager was removed from ASP.NET Ajax Control Toolkit source code in v15.1. This file was extracted from .NET Framework's System.Web.Extensions assembly, so you can provide your feedback to Microsoft using this site: http://referencesource.microsoft.com/