在论坛中看到有人问如何可以让任意Windows窗口置顶，这里其实可以使用Windows API函数SetWindowsPos做到。以下是示例代码：
示例代码演示将一个新打开的记事本程序置顶
1 [DllImport("user32.dll", SetLastError = true)]
2 public static extern IntPtr FindWindow(string lpClassName, string lpWindowName);
3
4 [DllImport("user32.dll")]
5 public static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int x, int y, int cx, int cy, uint uFlags);
6
7 public static readonly IntPtr HWND_TOPMOST = new IntPtr(-1); //窗体置顶
8 public static readonly IntPtr HWND_NOTOPMOST = new IntPtr(-2); //取消窗体置顶
9 public const uint SWP_NOMOVE = 0x0002; //不调整窗体位置
10 public const uint SWP_NOSIZE = 0x0001; //不调整窗体大小
11
12 private void button1_Click(object sender, EventArgs e)
13 {
14 //找到默认的打开的记事本程序
15 IntPtr notepadHandle = FindWindow(null, "无标题 - 记事本");
16 if (notepadHandle == null || notepadHandle == IntPtr.Zero)
17 return;
18 SetWindowPos(notepadHandle, HWND_TOPMOST, 1, 1, 1, 1, SWP_NOMOVE | SWP_NOSIZE);
19 }
2 public static extern IntPtr FindWindow(string lpClassName, string lpWindowName);
3
4 [DllImport("user32.dll")]
5 public static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int x, int y, int cx, int cy, uint uFlags);
6
7 public static readonly IntPtr HWND_TOPMOST = new IntPtr(-1); //窗体置顶
8 public static readonly IntPtr HWND_NOTOPMOST = new IntPtr(-2); //取消窗体置顶
9 public const uint SWP_NOMOVE = 0x0002; //不调整窗体位置
10 public const uint SWP_NOSIZE = 0x0001; //不调整窗体大小
11
12 private void button1_Click(object sender, EventArgs e)
13 {
14 //找到默认的打开的记事本程序
15 IntPtr notepadHandle = FindWindow(null, "无标题 - 记事本");
16 if (notepadHandle == null || notepadHandle == IntPtr.Zero)
17 return;
18 SetWindowPos(notepadHandle, HWND_TOPMOST, 1, 1, 1, 1, SWP_NOMOVE | SWP_NOSIZE);
19 }