WPF 为每个屏幕创建一个窗口，并将它们在每个屏幕上居中

本文关键字：屏幕 一个 创建 窗口 WPF | 更新日期: 2023-09-27 17:57:09

编辑：我解决了。在下面的答案中查看我的修复。

我正在开发一个应用程序，该应用程序应该在连接到运行它的计算机的每个屏幕上打开一个小弹出窗口。在单个屏幕上完成（使用 WindowStartupLocation = CenterScreen）非常简单，但在多个屏幕上完成却出奇地困难。

我当前的代码是这样的：

        foreach (var s in Screen.AllScreens) //System.Windows.Forms.Screen
        {
            var b = s.Bounds;
            var w = new PopupWindow();
            var oW = w.Width; //Keep track of original size ...
            var oH = w.Height;
            w.Width = 0; //then set the size to 0, to avoid that the 
            w.Height = 0;//popup shows before it is correctly positioned
            w.Show(); //Now show it, so that we can place it (when I
                      //tried to place it before showing, the window
                      //was always repositioned when Show() was called)
            double dpiX = 1, dpiY = 1;
            var presentationsource = PresentationSource.FromVisual(w);
            if (presentationsource != null)
            {
                dpiX = presentationsource.CompositionTarget.TransformToDevice.M11;
                dpiY = presentationsource.CompositionTarget.TransformToDevice.M22;
            }
            var aW = oW*dpiX; //Calculate the actual size of the window
            var aH = oH*dpiY;
            //***** THIS IS WRONG, SEE ANSWER *****
            w.Left = (b.X + (b.Width / dpiX - aW) / 2); //Place it
            w.Top = (b.Y + (b.Height / dpiY - aH) / 2);
            //*************************************
            w.Width = oW; //And set the size back to the original size
            w.Height = oH;
        }

这似乎仅适用于主屏幕。在其他屏幕上，窗口未正确居中。

我想这是因为我对 WPF 和 DPI 的了解非常有限，我可能做错了什么。有人能指出我正确的方向吗？

WPF 为每个屏幕创建一个窗口，并将它们在每个屏幕上居中

当然，我在这里发布后设法解决了它。当我尝试使用 DPI 划分整个位置时，看起来我做错了其他事情，这导致我走上了上面发布的错误路径。

放置表单的正确行应该是这样的（所有其他代码都有效）：

                w.Left = (b.X + (b.Width - aW) / 2) / dpiX;
                w.Top = (b.Y + (b.Height - aH) / 2) / dpiX;

但是，我仍然认为这是一个简单任务的大量代码，所以如果有人有更好的想法，请告诉我！

所以这是我现在使用的（工作）代码：

    foreach (var s in Screen.AllScreens) //System.Windows.Forms.Screen
    {
        var b = s.Bounds;
        var w = new PopupWindow();
        var oW = w.Width; //Keep track of original size ...
        var oH = w.Height;
        w.Width = 0; //then set the size to 0, to avoid that the 
        w.Height = 0;//popup shows before it is correctly positioned
        w.Show(); //Now show it, so that we can place it (when I
                  //tried to place it before showing, the window
                  //was always repositioned when Show() was called)
        double dpiX = 1, dpiY = 1;
        var ps = PresentationSource.FromVisual(w);
        if (ps != null)
        {
            dpiX = ps.CompositionTarget.TransformToDevice.M11;
            dpiY = ps.CompositionTarget.TransformToDevice.M22;
        }
        var aW = oW*dpiX; //Calculate the actual size of the window
        var aH = oH*dpiY;
        w.Left = (b.X + (b.Width - aW) / 2) / dpiX;
        w.Top = (b.Y + (b.Height - aH) / 2) / dpiX;
        w.Width = oW; //And set the size back to the original size
        w.Height = oH;
    }

        var centers =
            System.Windows.Forms.Screen.AllScreens.Select(
                s =>
                    new
                    {
                        Left = s.Bounds.X + (s.WorkingArea.Right - s.WorkingArea.Left)/2,
                        Top = s.Bounds.Y + (s.WorkingArea.Bottom - s.WorkingArea.Top)/2
                    });
        foreach (var c in centers)
        {
            var w = new Window1();
            w.Left = c.Left - w.Width/2;
            w.Top = c.Top - w.Height/2;
            w.Show();
        }
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