CODEWITHSUNDEEP
c#.netwinformseventsbutton
sd_dracula
sd_dracula

Reputation: 3896

c# winforms events

In my c# winform app I have a button which when clicked, it performs some calculations which can tke some time.

I also have a label.visible = false which I would like to label.visible = true right after the button click so that the user can see the app working away.

The thing is even when label.visible = true is the first thing in the button1_Click(object sender, EventArgs e) method, it only toggles to visible at the very end, after the calculation is performed.

How can I show the label right after the button_click?

Upvotes: 2

Views: 456

Answers (4)

Botonomous
Botonomous

Reputation: 1764

Like others have said: You are performing your work on the UI Thread. I am showing you another valid way of achieving what you need. You can move your work to a separate thread using an anonymous delegate. 

(new System.Threading.Thread(() =>
        {
            dowork(); // What ever work you need put here.
        })).Start();

Upvotes: 1

Dave Bish
Dave Bish

Reputation: 19656

If you need your application to remain responsive whilst your app is processing, take a look at Background Worker

You can force your form to update & process any background messages by calling:

Application.DoEvents();

Just after you have changed your label - although this is probably a bit of a hacky solution.

Upvotes: 4

Roy Dictus
Roy Dictus

Reputation: 33149

There are several ways to tackle this.

One way (the simplest) is to call

this.Refresh();

right after you set the Label to visible.

Another is to do your calculations in a background thread. The easiest way to do that is to use a BackgroundWorker. Then your main thread can just continue serving the UI (refreshing the form, responding to buttons etc.) while the background worker thread performs the computation.

See http://www.dotnetperls.com/backgroundworker for more on background worker threads.

Upvotes: 1

Justin Harvey
Justin Harvey

Reputation: 14682

Your calculation is being performed on the UI thread. This means that it is blocking the UI from refresshing after you have set the visibility of the label. You should consider doing the calculation on another thread using a Task. This will allow the UI to be responsive during what it seems is a long operation that can run in the background.

e.g.

var taskCalc = Task.Factory.StartNew(() => //Do Calculation );

Upvotes: 2

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