[C#] Foreach freezing application

[WiredUp]

I have a very long foreach loop that searches the hard drive. However, once the application enters the foreach loop, you can't interact with the application. I want to create a progress bar, but since the application is frozen up until the loop is finished, it's pretty much purposeless. How can I use foreach loops without freezing up the application?

[azcodemonkey]

You need to use threads. In .NET 2.0 there is a BackgroundWorker class, but in anything earlier, you'll have to thread manually.

[amrinders87]

^^ You beat me by editing your post. :laugh:

You need to put the loop on a separate thread. Use the BackgroundWorker if you are using .Net 2.0. It supports reporting progress.

[WiredUp]

What if I'm using .NET 1.1? How do I thread manually in .NET 1.1? Any sample code?

[WiredUp]

Edit: Nvm, I was able to figure it out. And I was able to access my form from the function.

Edited August 21, 2007 by WiredUp

[Linkinfamous]

"And I was able to access my form from the function. "

It will work some of the time, but there's no question that it will fail. You need to invoke things on it, they're not Threadsafe.

[WiredUp]

These long-running threads seem to lag down my computer. Also, when I close the application, Visual Studio still shows it's running (the pause and stop buttons are still active). It appears it's still running the function as Visual Studio still throws exceptions eventually when I search a directory I do not have access to (several minutes after I already closed the application). How can I fix this?

Edited August 22, 2007 by WiredUp

[Linkinfamous]

You need to stop the thread when your form closes. Call Abort() on the thread.

The main window is running on the app's main thread, and killing it won't kill this.

[WiredUp]

OK, last threading question I hope. How can I tell if the thread is done? It appears once the search finishes, the thread automatically closes. However, I don't know how to detect this.

[+Majesticmerc MVC]

If it's just for the GUI, use a delegate to update the GUI before the thread closes, instead of getting the GUI thread to do the work when the thread exits.

Alternatively, you could try doing something with the Thread.isAlive property.

You could also use a boolean to determine when the thread completes...

i.e. Declare a boolean at class level, then when the thread has finished processing the function that was in the thread should set the Boolean to TRUE. Other functions could then check this boolean.

[Linkinfamous]

Here's a great intro to .NET Threading:

http://www.albahari.com/threading/index.html

Some of it only pertains to .NET 2.0, but that's mostly the later stuff.