Comments on: C# .NET – UI Threading Example

By: francisco

francisco — Wed, 01 Sep 2010 20:10:32 +0000

i was stuck with my degree project because of the “only UI thread can modify UI elements” problem. thanks!! :)

By: doug

doug — Tue, 27 Jul 2010 01:16:24 +0000

Glad to hear it, Jim! Thanks.

By: Jim

Jim — Mon, 26 Jul 2010 23:19:04 +0000

Hi Doug,

Just a quick Thanks!! for posting your article. After digging through the C# 4.0 Nutshell book and numerous examples on the ‘net, yours is the first example that is straightforward, understandable, and actually worked when I used it as an example in my thread-to-UI update code. Jim

By: Frank

Frank — Mon, 18 Jan 2010 13:53:15 +0000

Hi, I like the simplicity of your example. However, I wonder how the following situation should be resolved:

If you start the “worker in a new thread” and close the form BEFORE it has completed, the application crashes.

Any idea on how to deal with this situation?

By: Al

Al — Mon, 23 Nov 2009 19:04:42 +0000

i think the lock{} is only needed for shared variables. i.e. if you have more than one thread writing to that textbox. if there’s another thread writing to that same text box you want to make sure it waits until the first thread finishes. to keep concurrency.

By: doug

doug — Sun, 15 Nov 2009 22:13:32 +0000

Raj – thanks for the comment. I am definitely NOT an expert, but I don’t see why we need a lock here. Using a lock might be a technically safer thing to do on paper, but in reality I’m not sure that it makes any difference. It’s certainly the case that my code above with no lock will never generate an exception, but it might be true that if you apply the above principles to larger projects a lock might become necessary. Once again though, I don’t claim to be an expert. I’ve only posted this because I think it’s it’s the easiest way to illustrate a simple UI that utilizes multiple threads.

I’d love for you to explain why we need a lock here. I’m always open to learn new things.

-Doug

By: Raj

Raj — Sun, 15 Nov 2009 01:58:08 +0000

Dont we need to put the method populateTextBox inside a lock ?

void populateTextBox(string text)
{
lock(this)
{
textBox1.Text = textBox1.Text + ” ” + text;
}
}