The thread from the thread pool will do the callback after it executes the method.Windows Forms poses a set of complicated design and implementation issues when it comes to asynchronous method invocation and multithreading.NET Programming", Co De Magazine, May 2003) you cannot apply it as-is in a Windows Forms application. NET (version 2.0, code-name Whidbey) provides a new component designed to ease the task of developing asynchronous Windows Forms applications.This article starts by describing the current asynchronous programming model available to Windows Forms developers.Microsoft is conducting an online survey to understand your opinion of the Msdn Web site.If you choose to participate, the online survey will be presented to you when you leave the Msdn Web site. This pitfall of this solution is that Update Rich Text Box has to be carefully written as it is being called re-entrantly on two different threads.
You need to be familiar with a few additional details including how to gain access to the original delegate used to invoke the call from within the completion callback, but in general, the programming model just described is sufficient for most applications, except when it comes to Windows Forms. First, any decent client application should want to display some progress or indication of the current status of the asynchronous task to the user.
This isn’t really helpful for passing back custom data to the control.