如何获得最顶层形式的手柄一个WinForm应用程序？

问题描述

我有了其他的子窗体（不MDI）一个WinForm程序。如果即使它不具有焦点的用户pressesEsc键的最顶层形式应该关闭。

I have a WinForm app that has other child forms (not mdi). If the user presses "Esc" the topmost form should be closed even if it doesn't have the focus.

我可以使用键盘钩子在全球范围内赶上逃走，但我也需要形式的句柄被关闭。

I can use a keyboard hook to globally catch the Escape but I also need the handle of the form to be closed.

我想有一个办法做到这一点使用Win32 API，但有使用管理code的解决方案？

I guess there is a way to do that using Win32 API, but is there a solution using managed code?

推荐答案

下面是获得使用Win32的最顶端窗体的一种方式（不是很优雅，但它的工作原理）：

Here is one way to get the topmost form that uses Win32 (not very elegant, but it works):

public const int GW_HWNDNEXT = 2; // The next window is below the specified window
public const int GW_HWNDPREV = 3; // The previous window is above

[DllImport("user32.dll")]
static extern IntPtr GetTopWindow(IntPtr hWnd);

[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool IsWindowVisible(IntPtr hWnd);

[DllImport("user32.dll", CharSet = CharSet.Auto, EntryPoint = "GetWindow", SetLastError = true)]
public static extern IntPtr GetNextWindow(IntPtr hwnd, [MarshalAs(UnmanagedType.U4)] int wFlag);

/// <summary>
/// Searches for the topmost visible form of your app in all the forms opened in the current Windows session.
/// </summary>
/// <param name="hWnd_mainFrm">Handle of the main form</param>
/// <returns>The Form that is currently TopMost, or null</returns>
public static Form GetTopMostWindow(IntPtr hWnd_mainFrm)
{
    Form frm = null;

    IntPtr hwnd = GetTopWindow((IntPtr)null);
    if (hwnd != IntPtr.Zero)
    {
        while ((!IsWindowVisible(hwnd) || frm == null) && hwnd != hWnd_mainFrm)
        {
            // Get next window under the current handler
            hwnd = GetNextWindow(hwnd, GW_HWNDNEXT);

            try
            {
                frm = (Form)Form.FromHandle(hwnd);
            }
            catch
            {
                // Weird behaviour: In some cases, trying to cast to a Form a handle of an object 
                // that isn't a form will just return null. In other cases, will throw an exception.
            }
        }
    }

    return frm;
}

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