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I know WPF has a "CenterScreen" value for centering a window on the desktop. However, on dual monitor, that is not very pleasant.

How do I center on primary monitor? Do i need to go through the song and dance of detecting the primary desktop, get its geometry, etc, or is there a better way?

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4 回答 4

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Multiple screens are a bit of a problem and it does not have a built in, nicely wrraped way to handle them, but with some math and SystemParameters you can get it done.

If you position your window at position (0,0) that would be the top left corner of you primary screen. So in order to make your window appear in the center of that screen use:

this.Left = (SystemParameters.PrimaryScreenWidth / 2) - (this.ActualWidth / 2);
this.Top = (SystemParameters.PrimaryScreenHeight / 2) - (this.ActualHeight / 2);

The basic idea is simple enough so no need to explain.

Note this code is for C#, but i am sure VB has something similar.

Also note you should use the ActualWidth\ActualHeight property and not the Width\Height property as it could hold a NaN value.

Good luck.

于 2009-09-08T12:55:20.987 回答
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We had the same issue. Unfortunately, after much discussion with TA's and the client it was decided to be better value (in terms of money and time) to maximise it on the primary monitor.

于 2009-09-08T05:28:31.073 回答
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Use SystemParameters.WorkArea. That gives you part of the primary monitor that's not taken up by the task bar, which should give you nicer centering.

于 2011-08-11T17:54:41.077 回答
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This is my purely WPF solution to center a Window on the primary monitor with a border of empty space around it (because I don't want it maximized). My setup is a square-ish monitor on my left and a widescreen on my right. This was tested with each monitor being set as the primary monitor in Windows.

Before I get to that solution, there are three useful properties on System.Windows.SystemParameters that give various heights. The numbers given are for my 1920x1080 widescreen.

  • PrimaryScreenHeight - 1080. The actual resolution height set in Windows.
  • WorkArea.Height - 1040. The actual resolution height minus the Start Bar
  • FullPrimaryScreenHeight - 1018. The actual resolution minus the Start Bar and minus the Window header.

This is my solution and I use WorkArea.Height:

    protected T SetWindowLocation<T>(T window) where T : Window
    {
        //This function will set a window to appear in the center of the user's primary monitor.
        //Size will be set dynamically based on resoulution but will not shrink below a certain size nor grow above a certain size

        //Desired size constraints.  Makes sure window isn't too small if the users monitor doesn't meet the minimum, but also not too big on large monitors
        //Min: 1024w x 768h
        //Max: 1400w x 900h

        const int absoluteMinWidth = 1024;
        const int absoluteMinHeight = 768;
        const int absoluteMaxWidth = 1400;
        const int absoluteMaxHeight = 900;

        var maxHeightForMonitor = System.Windows.SystemParameters.WorkArea.Height - 100;
        var maxWidthForMonitor = System.Windows.SystemParameters.WorkArea.Width - 100;

        var height = Math.Min(Math.Max(maxHeightForMonitor, absoluteMinHeight), absoluteMaxHeight);
        var width = Math.Min(Math.Max(maxWidthForMonitor, absoluteMinWidth), absoluteMaxWidth);

        window.Height = height;
        window.Width = width;
        window.Left = (System.Windows.SystemParameters.FullPrimaryScreenWidth - width) / 2;
        window.Top = (System.Windows.SystemParameters.FullPrimaryScreenHeight - height) / 2;
        window.WindowStartupLocation = WindowStartupLocation.Manual;

        return window;
    }
于 2013-04-17T17:37:19.353 回答