Problems with PrimaryScreen.Size

Question

I've been fine with Screen.PrimaryScreen.Bounds.Size for some time, but on my Windows7 computer attached to my big-screen TV it is giving me incorrect values.

I read elsewhere to try SystemInformation.PrimaryMonitorSize but that gives the same values.

When I right click the desktop to get Screen Resolution, it says 1920x1080. The above two are giving me 1280x720.

I've also tried the WPF versions:

var w = System.Windows.SystemParameters.PrimaryScreenWidth;
var h = System.Windows.SystemParameters.PrimaryScreenHeight;
MessageBox.Show(new Size((int)w, (int)h).ToString());

The display size has been changed via the (right click the desktop) Personalize > Desktop options to be 150% (since the screen is 60" and you sit kind of far away).

How to detect this so the value's returned from the above can be adjusted?

Note: I've discovered how to get around this with a right-click executable and adjust the compatability to disable DPI virtualization, but I still need a programatic solution so I don't have to have user's adjust this themselves: See - http://msdn.microsoft.com/en-us/library/dd464660(VS.85).aspx#dpi_virtualization

@Grant What do you mean? The screen resolution is `1920x1080`, there is no secondary display. The computer is not a laptop. — Chuck Savage, Mar 07 '13 at 21:07
At 150%, you explicitly have to tell Windows that you are DPI aware on don't need to be lied to. — Hans Passant, Mar 07 '13 at 23:49
possible duplicate of [Winforms high DPI blurry fonts](http://stackoverflow.com/questions/13228185/winforms-high-dpi-blurry-fonts) — Hans Passant, Mar 07 '13 at 23:49
@HansPassant So there is no way to detect this from within the application? I've tried setting the manifest to test that, but I get a null error in a core lib. — Chuck Savage, Mar 08 '13 at 00:11
@HansPassant I copied the manifest from the link over my manifest, and get the error "Value cannot be null.\r\nParameter name: activationContext" — Chuck Savage, Mar 08 '13 at 00:18
You did something wrong, hard to guess. The linked duplicate also shows how to do it without a manifest. There's no point in "detecting it", your app is either dpi aware or it isn't. — Hans Passant, Mar 08 '13 at 00:20
@HansPassant It must be, because I created a new WinForms project, did the exact same thing and it runs w/o the error. — Chuck Savage, Mar 08 '13 at 00:27

score 6 · Answer 1 · edited Aug 20 '20 at 16:53

6

It could be your Dpi setting in windows set above 100%

Try using this method, this will scale the resolution to the current system Dpi settings

Winforms:

private Size GetDpiSafeResolution()
{
    using (Graphics graphics = this.CreateGraphics())
    {
        return new Size((Screen.PrimaryScreen.Bounds.Width * (int)graphics.DpiX) / 96
          , (Screen.PrimaryScreen.Bounds.Height * (int)graphics.DpiY) / 96);
    }
}

WPF:

private Size GetDpiSafeResolution()
{
    PresentationSource _presentationSource = PresentationSource.FromVisual(Application.Current.MainWindow);
    Matrix matix = _presentationSource.CompositionTarget.TransformToDevice;
    return new System.Windows.Size(
        System.Windows.SystemParameters.PrimaryScreenWidth * matix.M22,
        System.Windows.SystemParameters.PrimaryScreenHeight * matix.M11);
}

Note: Make sure your MainWindow is loaded before running this code

edited Aug 20 '20 at 16:53

Chuck Savage

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answered Mar 07 '13 at 21:53

sa_ddam213

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This is a winforms application, so I'm having troubles getting Application.Current – Chuck Savage Mar 07 '13 at 22:01
sorry I thought it was wpf :( – sa_ddam213 Mar 07 '13 at 22:02
Updated my answer with Winforms version (untested). But its the same idea, you need to find the Dpi setting and mutiply the size by that – sa_ddam213 Mar 07 '13 at 22:09
Thx, why do you declare the two float dpiX and dpiY values but don't use them? – Chuck Savage Mar 07 '13 at 22:11
That's not helping, that just multiplies 1280 by 96 and 720 by 96. They need to be multiplied by 1.5 – Chuck Savage Mar 07 '13 at 22:17
Can you test my latest version, I cant test as I cant restart my PC right now to change my Dpi, (sorry i am bad at math and this confused me a bit LOL) – sa_ddam213 Mar 07 '13 at 22:25
I tried that already, but graphics.DpiX is 96. Thanks for the effort. – Chuck Savage Mar 07 '13 at 22:25
oh so you dpi is 96, hmm Then I wonder why you get the wrong value from `Screen.PrimaryScreen` – sa_ddam213 Mar 07 '13 at 22:26
Right, all that is happening (from what I gather from the dialog box) is that items are just getting increased 150%, the screen itself isn't changing. Yet the normal way to get the screen size is smaller - for whatever reason. – Chuck Savage Mar 07 '13 at 22:28
Try setting this in the Form constructor `AutoScaleMode = System.Windows.Forms.AutoScaleMode.None;` – sa_ddam213 Mar 07 '13 at 22:30
I thought about trying that, as it is an imperfect solution (if it worked) - but it doesn't help - just tested it. – Chuck Savage Mar 07 '13 at 22:37
1

Its been so long since I have used winforms, sorry i could not help :( – sa_ddam213 Mar 07 '13 at 22:42
1

Thanks for your efforts, please don't delete this as there is valuable information we discussed in our comments that might help others. – Chuck Savage Mar 07 '13 at 22:44
Thanks again, just tried the WPF answer. It's great, but the width & height were backwards, edited the answer to correct it. – Chuck Savage Aug 20 '20 at 16:54

score 4 · Accepted Answer · edited May 23 '17 at 12:10

4

I don't feel this is a duplicate question, but the answer is the same as on another thread: https://stackoverflow.com/a/13228495/353147 As the question isn't about blurry fonts but why Screen.PrimaryScreen.Bounds.Size returns faulty information. It could help others.

I did run into an error message, that mscorlib threw an null error. From this thread http://forums.asp.net/t/1653876.aspx/1 I was able to discover that unchecking "Enable ClickOnce security settings" fixed it. This seems like a hack, but it works.

edited May 23 '17 at 12:10

Community

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answered Mar 08 '13 at 00:41

Chuck Savage

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First link is best solution, it solved my problem in 2 lines of code. – Profesor08 Jan 09 '19 at 12:41

Problems with PrimaryScreen.Size

2 Answers2

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