通过调用Win32 API实现。
复制代码 代码如下:
public class User32API
{
private static Hashtable processWnd = null;

public delegate bool WNDENUMPROC(IntPtr hwnd, uint lParam);

static User32API()
{
if (processWnd == null)
{
processWnd = new Hashtable();
}
}

[DllImport("user32.dll", EntryPoint = "EnumWindows", SetLastError = true)]
public static extern bool EnumWindows(WNDENUMPROC lpEnumFunc, uint lParam);

[DllImport("user32.dll", EntryPoint = "GetParent", SetLastError = true)]
public static extern IntPtr GetParent(IntPtr hWnd);

[DllImport("user32.dll", EntryPoint = "GetWindowThreadProcessId")]
public static extern uint GetWindowThreadProcessId(IntPtr hWnd, ref uint lpdwProcessId);

[DllImport("user32.dll", EntryPoint = "IsWindow")]
public static extern bool IsWindow(IntPtr hWnd);

[DllImport("kernel32.dll", EntryPoint = "SetLastError")]
public static extern void SetLastError(uint dwErrCode);

public static IntPtr GetCurrentWindowHandle()
{
IntPtr ptrWnd = IntPtr.Zero;
uint uiPid = (uint)Process.GetCurrentProcess().Id; // 当前进程 ID
object objWnd = processWnd[uiPid];

if (objWnd != null)
{
ptrWnd = (IntPtr)objWnd;
if (ptrWnd != IntPtr.Zero && IsWindow(ptrWnd)) // 从缓存中获取句柄
{
return ptrWnd;
}
else
{
ptrWnd = IntPtr.Zero;
}
}

bool bResult = EnumWindows(new WNDENUMPROC(EnumWindowsProc), uiPid);
// 枚举窗口返回 false 并且没有错误号时表明获取成功
if (!bResult && Marshal.GetLastWin32Error() == 0)
{
objWnd = processWnd[uiPid];
if (objWnd != null)
{
ptrWnd = (IntPtr)objWnd;
}
}

return ptrWnd;
}

private static bool EnumWindowsProc(IntPtr hwnd, uint lParam)
{
uint uiPid = 0;

if (GetParent(hwnd) == IntPtr.Zero)
{
GetWindowThreadProcessId(hwnd, ref uiPid);
if (uiPid == lParam) // 找到进程对应的主窗口句柄
{
processWnd[uiPid] = hwnd; // 把句柄缓存起来
SetLastError(0); // 设置无错误
return false; // 返回 false 以终止枚举窗口
}
}

return true;
}
}

调用User32API.GetCurrentWindowHandle()即可返回当前进程的主窗口句柄，如果获取失败则返回IntPtr.Zero。

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