Re: Windows form controls reposition when DPI changes - C# Discussion Boards

Re: Windows form controls reposition when DPI changes

12-Dec-14 14:06

It is not an anomaly. Look into docking and anchoring, that'll automatically resize them as desired.

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robwm115-Dec-14 7:56

Re: Windows form controls reposition when DPI changes

15-Dec-14 7:56

I did a quick check and all of my controls are Anchored: Top, Left by default. I noticed that Dock is set to None for the same controls. I'm looking into the Dock property now.

It doesn't look like you can use both at the same time according to MSDN:
"The Anchor and Dock properties are mutually exclusive. Only one can be set at a time, and the last one set takes precedence."

modified 15-Dec-14 14:07pm.

Eddy Vluggen16-Dec-14 0:28

Re: Windows form controls reposition when DPI changes

16-Dec-14 0:28

They're both used to grow/shrink the control, to fill up to empty space as designed. The form might have different dimensions on another PC, due to resolution, size of the screen and the amount of pixels per inch.

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robwm116-Dec-14 5:42

Re: Windows form controls reposition when DPI changes

16-Dec-14 5:42

After experimenting with the Anchor property, I have most of the form looking alright after making changes. I don't think the Dock property is going to work for this project. It seems like the labels will need to be manipulated at runtime.

Here is a link to screenshots of the different DPI states:
Screenshots with different DPI settings applied

The top screenshot is how I want it to look across any of the default Windows DPI settings if that is possible.

This is how the Anchor property is configured for each of the controls.

Image upper left - Anchor = Top, Left
Title label upper right - Anchor = Top, Right
Enter Credentials label - Anchor = Top, Left
First Name label - Anchor = Top, Left
First Name textbox - Anchor = Top, Right
Last Name label - Anchor = Top, Left
Last Name textbox - Anchor = Top, Right
Username label - Anchor = Top, Left
Username textbox - Anchor = Top, Right
Abort button - Anchor = Bottom, Right
Backup button - Anchor = Bottom, Right

Any other suggestions as to how to make this work properly?

I'm thinking at this point that I should get the current DPI setting and if it's greater than 96 dpi then move the x-coordinate of the labels.

modified 16-Dec-14 11:59am.

Eddy Vluggen16-Dec-14 5:58

Re: Windows form controls reposition when DPI changes

16-Dec-14 5:58

In WinForms, I'd try and center the title-text on the form; that way it could grow in both directions. I assume you're talking about the title, as the rest looks quite good.

robwm1 wrote:
I'm thinking at this point that I should get the current DPI setting and if it's greater than 96 dpi then move the x-coordinate of the labels.

If the label is autogrowing, then that "could" be enough. It may overlap other controls though if it grows.

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robwm116-Dec-14 6:59

Re: Windows form controls reposition when DPI changes

16-Dec-14 6:59

The title "File Archiver Utility" is in a label. The label itself wraps tightly around the text and the text-align property is set to MiddleCenter and AutoSize is set to True. I might be able to get away with making a banner that includes the logo and title because the image seems to scale or just move the label to the left at launch. I have a couple of other labels that are to the right as well so moving them at launch is probably the best approach.

Eddy Vluggen16-Dec-14 7:33

Re: Windows form controls reposition when DPI changes

16-Dec-14 7:33

robwm1 wrote:
The label itself wraps tightly around the text and the text-align property is
set to MiddleCenter and AutoSize is set to True

Alignment doesn't help then, as the size of the label is as small as possible. There's no wiggle-room then.

Disable autosizing and make it as wide as the form (the maximum size it should be allowed to be), then anchor it, and then "align middle" will work better.

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robwm116-Dec-14 7:39

Re: Windows form controls reposition when DPI changes

16-Dec-14 7:39

I made the label the full width from the right edge of the logo graphic to the right edge of the window. Although the text isn't aligned proportionally the same as when DPI is 100%, I would say it falls into the "good enough" category. I'm going to try changing the X location to see how that works.

I could probably put the left edge of the label to where I want the text to be aligned when DPI is 125% and then change the alignment of the box to LeftCenter.

robwm116-Dec-14 11:46

Re: Windows form controls reposition when DPI changes

16-Dec-14 11:46

So getting the DPI setting and changing the control's Location property pretty easily solves this matter. This way I can make the two 'views' look the same without much trouble.

Thanks a lot for your help, Eddy!

Eddy Vluggen17-Dec-14 0:27

17-Dec-14 0:27

You're welcome Smile | :)

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Bitmap Dispose

V.12-Dec-14 2:26

12-Dec-14 2:26

Suppose I have following code. (not necessarily in one function or even one class.)

System.Drawing.Bitmap bmp = new System.Drawing.Bitmap("[path]");
//do stuff
bmp.Dispose();

How can I detect if bmp was disposed or not? it is not set to null when calling Dispose, but trying to check a property (ef width and height) to see if it is a valid property immediately results in an exception being thrown.

I searched google, but found not real satisfactory option. I try to set bmp = null where I can after dispose, but this is not always and option. (for one thing, this application is a heritage of someone else Wink | ;-)

)

thanks.

V.

(MQOTD rules and previous solutions)

Imperative to Functional Programming Succinctly

Contributors Wanted for Higher Order Programming Project!

Marc Clifton12-Dec-14 3:11

Marc Clifton

12-Dec-14 3:11

One somewhat horrible way of doing this is:

Bitmap bitmap = new Bitmap(200, 200);
IntPtr hBitmap1 = bitmap.GetHbitmap(); // No exception because bitmap hasn't been disposed.

bitmap.Dispose();

try
{
	IntPtr hBitmap2 = bitmap.GetHbitmap();
}
catch (ArgumentException ex)
{
	Console.WriteLine("Bitmap has been disposed!");
}

Otherwise, you might try figuring out how to test the native handle.

[edit] BTW, I tried reflection to see if Bitmap or Image has a "disposed" field or property. No such luck. [/edit]

Marc

OriginalGriff12-Dec-14 3:55

12-Dec-14 3:55

There is no way to find out if an object is disposed AFAIK, other than to try and use it and catch the ObjectDisposedException exception.

The problem is that Dispose releases all memory for the object, so there is nothing there at the reference instance to hold info for "this is disposed"! Laugh | :laugh:

You could add your own bool and check that, but it does seem like a nasty kludge.

Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...

Richard Andrew x6412-Dec-14 7:20

Richard Andrew x64

12-Dec-14 7:20

You could derive a class of your own from Bitmap, and add a Disposed property that tracks whether the object has been disposed.

You would need to override the Dispose method to set the flag to true.

The difficult we do right away...
...the impossible takes slightly longer.

OriginalGriff12-Dec-14 8:14

12-Dec-14 8:14

Not sure that would work, since the flag would be Disposed at the same time as the rest of it. At best, it would risk problems with consistency once the GC kicked in, wouldn't it?

He could get away with encapsulating a Bitmap, and Disposing that without disposing the outer object, but...

Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...

Richard Andrew x6412-Dec-14 8:16

Richard Andrew x64

12-Dec-14 8:16

You're right. I guess I didn't engage the brain before the fingers. Blush | :O

The difficult we do right away...
...the impossible takes slightly longer.

Richard Andrew x6412-Dec-14 8:31

Richard Andrew x64

12-Dec-14 8:31

On second thought, I thought the purpose of Dispose is to release unmanaged resources.

The managed memory of an object would remain valid until it goes out of scope, no?

The difficult we do right away...
...the impossible takes slightly longer.

OriginalGriff13-Dec-14 0:19

13-Dec-14 0:19

I was thinking about all this when I went to bed last night, and it's really quite nasty. And yes, you are absolutely right: Disposed objects are not deallocated until they go out of scope - My mistake Blush | :O

So I thought Id give it a try today. And got real problems trying to derive a class and dispose it. Until I finally twigged: You can't derive from a Bitmap anyway: it's a sealed class...http://msdn.microsoft.com/en-us/library/system.drawing.bitmap%28v=vs.110%29.aspx[^]

You can derive from non-sealed disposable classes, and add variables (which you are absolutely right, won't be deallocated until they go out of scope), but...MSDN says you shouldn't!
"An ObjectDisposedException is thrown when you try to access a member of an object that implements the IDisposable interface, and that object has been disposed. Typically, this exception is caused by one of the following conditions:" http://msdn.microsoft.com/en-us/library/system.objectdisposedexception(v=vs.110).aspx[^]
So the way I read it is that if an object is Disposed, you should get an exception whenever you try to use it again - I know you don't, but technically you should.

And the OP is back to encapsulation! Laugh | :laugh:

Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...

Richard Deeming15-Dec-14 2:15

Richard Deeming

15-Dec-14 2:15

OriginalGriff wrote:
Until I finally twigged: You can't derive from a Bitmap anyway: it's a sealed class...

Ahem![^]

Richard Deeming wrote:

The only problem is, you can't write a class derived from Bitmap, as it's sealed.

That'll learn ya to ignore your notifications! Poke tongue | ;-P

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- Homer

OriginalGriff15-Dec-14 2:27

15-Dec-14 2:27

Everyone knows I can't read... Laugh | :laugh:

Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...

Richard Deeming12-Dec-14 8:56

Richard Deeming

12-Dec-14 8:56

A bool flag wouldn't be disposed. Plenty of classes in the BCL seem to use this approach - for example:
http://referencesource.microsoft.com/#mscorlib/system/threading/CancellationTokenSource.cs,135[^]

The only problem is, you can't write a class derived from Bitmap, as it's sealed.

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer