How to know if the dialog box is closed completely?

Question

I have a parent form Form1 which is opened in fullscreen mode. There's a button in Form1 which opens a form Form2 (using .ShowDialog() method). When the form is closed, the program captures the screenshot of the Form1. But in the screenshot I can still see the Form2 which still has some opacity during closing (I'm using Microsoft Windows 7 Pro which animates the closing of the form by reducing the opacity of the form).

So how can I know when the Form2 is 100% closed, so that I can take screen shot of the program?

Edit: I'm using Graphics.CopyFromScreen Method in Form1 to capture the screen shot.

And Form2 is closed by the button click in Form2 using this.Close() method.

I think this is because animations in windows theme. how do you capture screen shot of the form1? — Hamid Pourjam, Feb 17 '15 at 08:18
You should add your code that you use to close the form as well as the code that opens/screenshots it (presuming this is with `ShowDialog()`) — Sayse, Feb 17 '15 at 08:19
Related question: [Capture screenshot of active window?](http://stackoverflow.com/questions/1163761/capture-screenshot-of-active-window) — Sayse, Feb 17 '15 at 08:20
@L16H7 - You can possibly use `form.Visible` to see if it is still visible but I'd imagine this is flaky at best. The better option would be to actually screenshot the window rather than the screen — Sayse, Feb 17 '15 at 08:29

score 2 · Answer 1 · answered Feb 17 '15 at 08:29

2

I came up with an easy solution that contains no waiting.

add an handler to FormClosing event on Form2 and set its location to somewhere off screen.

private void Form2_FormClosing(object sender, FormClosingEventArgs e)
{
   this.Location = new Point(-4000,-4000);
}

answered Feb 17 '15 at 08:29

Hamid Pourjam

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This would be very annoying however if you wish to reopen the same dialog – Sayse Feb 17 '15 at 08:29
previous location can be stored and then restored on `Shown` @Sayse – Hamid Pourjam Feb 17 '15 at 08:32
@Sayse How can you reopen a disposed dialog? You'd have to create a new one in any case. – Rotem Feb 17 '15 at 08:53
closing a form is not disposing it. you can call close, showdialog as long as you have not disposed your form. @Rotem – Hamid Pourjam Feb 17 '15 at 08:55
@Rotem - Simply by closing it, doesn't necessarily fully dispose of it ([for example, see quote](http://stackoverflow.com/questions/16846573/using-dialogresult-correctly)) – Sayse Feb 17 '15 at 08:55
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`Thread.Sleep(1000)` solved the problem. Thanks for your efforts. – Bhaskar Feb 17 '15 at 09:06
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I've been living a lie! – Rotem Feb 17 '15 at 10:46

score 2 · Accepted Answer · edited May 23 '17 at 11:44

2

If there's a way to know for sure the Windows desktop manager animation has completed, it's not in .NET itself. You'd have to find a native API that provides this detail (and I'm not sure one exists…I'm not aware of one if it does) and execute it via p/invoke.

I think commenter/answerer dotctor has provided a couple of good options: just delay long enough to account for the animation, or shift the offending window out of the way as it's closing (and if you do reuse the same Form2 instance, shift it back before displaying it again).

That said, you might also consider using the Control.DrawToBitmap() method to do the screenshot, since you seem to want the image to be the full-screen image of the Form1 window. It has some limitations (which you can read about in the docs), but as long as none of those apply in your case, it might be a more convenient way to get the image you want.

edited May 23 '17 at 11:44

Community

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answered Feb 17 '15 at 08:49

Peter Duniho

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So how to create a delay of 1 sec.? – Bhaskar Feb 17 '15 at 08:55
`Thread.Sleep(1000)`, also it is not a good idea to call it on UI thread. @L16H7 – Hamid Pourjam Feb 17 '15 at 08:56
@L16H7: that's a whole separate question! :) You didn't offer enough of a code example to know how in _your_ code you should create the delay. You can use things like `System.Windows.Forms.Timer`, or `Task.Delay()`, for example. – Peter Duniho Feb 17 '15 at 08:57

How to know if the dialog box is closed completely?

2 Answers2