c#句柄管理：c#获取进程的主窗口句柄的例子

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;
}
}