确定 WPF window 位置，使其始终在屏幕边界内可见（如 OS 的右键单击上下文菜单）

Question

如您在图中所见，我想在 Launch window（WinForms 应用程序）的位置打开一个固定大小的 WPF window。如何确保即将打开的 WPF windows 放置在 Launch window 的任何一侧都完全可见。 Windows 桌面的右键单击菜单中有类似的行为，就好像您单击屏幕的最边缘一样，它会在左侧打开上下文菜单，如果您在屏幕中间，它会打开任一侧。

我已经尝试了一些东西，也尝试了这个 SO 答案，但仍在弄清楚如何计算 Windows 的边界，使其在可见区域内。 WPF determine element is visible on screen

Answer 1

过程将是：

使用其句柄获取 window 的矩形。
获取window所在监视器的句柄。
使用监视器的句柄获取监视器的信息（特别是工作区域的矩形）。
计算可用方向space.

using System;
using System.Runtime.InteropServices;

public enum Direction { None, TopLeft, TopRight, BottomRight, BottomLeft }

public static class WindowHelper
{
    public static Direction GetAvailableDirection(IntPtr windowHandle)
    {
        if (!GetWindowRect(windowHandle, out RECT buffer))
            return Direction.None;

        System.Drawing.Rectangle windowRect = buffer;

        IntPtr monitorHandle = MonitorFromWindow(windowHandle, MONITOR_DEFAULTTO.MONITOR_DEFAULTTONULL);
        if (monitorHandle == IntPtr.Zero)
            return Direction.None;

        MONITORINFO info = new() { cbSize = (uint)Marshal.SizeOf<MONITORINFO>() };
        if (!GetMonitorInfo(monitorHandle, ref info))
            return Direction.None;

        System.Drawing.Rectangle workingAreaRect = info.rcWork;

        bool isWindowAlignedTop = (windowRect.Top - workingAreaRect.Top) < (workingAreaRect.Bottom - windowRect.Bottom);
        bool isWindowAlignedLeft = (windowRect.Left - workingAreaRect.Left) < (workingAreaRect.Right - windowRect.Right);

        return (isWindowAlignedTop, isWindowAlignedLeft) switch
        {
            (true, true) => Direction.BottomRight,
            (true, false) => Direction.BottomLeft,
            (false, true) => Direction.TopRight,
            (false, false) => Direction.TopLeft
        };
    }

    [DllImport("User32.dll", SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool GetWindowRect(
        IntPtr hWnd,
        out RECT lpRect);

    [DllImport("User32.dll")]
    private static extern IntPtr MonitorFromWindow(
        IntPtr hwnd,
        MONITOR_DEFAULTTO dwFlags);

    private enum MONITOR_DEFAULTTO : uint
    {
        MONITOR_DEFAULTTONULL = 0x00000000,
        MONITOR_DEFAULTTOPRIMARY = 0x00000001,
        MONITOR_DEFAULTTONEAREST = 0x00000002,
    }

    [DllImport("User32.dll", CharSet = CharSet.Unicode)]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool GetMonitorInfo(
        IntPtr hMonitor,
        ref MONITORINFO lpmi);

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
    private struct MONITORINFO
    {
        public uint cbSize;
        public RECT rcMonitor;
        public RECT rcWork;
        public uint dwFlags;
    }

    [StructLayout(LayoutKind.Sequential)]
    private struct RECT
    {
        public int left;
        public int top;
        public int right;
        public int bottom;

        public static implicit operator System.Drawing.Rectangle(RECT rect)
        {
            return new System.Drawing.Rectangle(
                rect.left,
                rect.top,
                rect.right - rect.left,
                rect.bottom - rect.top);
        }
    }
}

请注意调用应用程序必须有一个应用程序清单，其中包括正确计算的 DPI 感知。

确定 WPF window 位置，使其始终在屏幕边界内可见（如 OS 的右键单击上下文菜单）

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