C# 设置最顶层窗口。TopMostWindow

code:

namespace LOLMM
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            Topmost = true;
            Loaded += new RoutedEventHandler(MainWindow_Loaded);
            t.Interval = TimeSpan.FromMilliseconds(300);
            t.Tick += new EventHandler(t_Tick);


        } 
        DispatcherTimer t = new DispatcherTimer();

        void t_Tick(object sender, EventArgs e)
        {
            TopMostWindow.SetTopomost(new WindowInteropHelper(this).Handle);
        }

        void MainWindow_Loaded(object sender, RoutedEventArgs e)
        {
            TopMostWindow.SetTopomost(new WindowInteropHelper(this).Handle);
            t.Start();
        }

    }
}

　　

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;

namespace LOLMM
{
    public class TopMostWindow
{
　　public const int HWND_TOP = 0;
　　public const int HWND_BOTTOM = 1;
　　public const int HWND_TOPMOST = -1;
　　public const int HWND_NOTOPMOST = -2;


　　[DllImport("user32.dll")]
　　public static extern IntPtr SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int x, int y, int cx, int cy, uint wFlags);


　　[DllImport("user32.dll")]　　
　　public static extern bool GetWindowRect(IntPtr hWnd, out WindowRect lpRect);

　　/// <summary>
　　/// 设置窗体为TopMost
　　/// </summary>
　　/// <param name="hWnd"></param>
　　public static void SetTopomost(IntPtr hWnd)
　　{
　　　　WindowRect rect = new WindowRect();
　　　　GetWindowRect(hWnd, out rect);
　　　　SetWindowPos(hWnd, (IntPtr)HWND_TOPMOST, rect.Left, rect.Top, rect.Right - rect.Left, rect.Bottom - rect.Top, 0);
　　}
}

public struct WindowRect
{
　　public int Left;
　　public int Top;
　　public int Right;
　　public int Bottom;
}


}
//调用方式：
//将此窗体设置为Topmost
//TopMostWindow.SetTopomost(new WindowInteropHelper(this).Handle);