LorDong's Blog

前段时间写的C#程序启动欢迎窗体实现，在运行时虽然能显示欢迎窗体，但运行后不能把主窗体提到最前。结合网上搜罗了好多资料，自己做了好几个方案来实现，最终可以解决了。

起因：
2000/XP 改变了SetForegroundWindow的执行方式，不允许随便把窗口提前，打扰用户的工作。

思路：
可以用附加本线程到最前面窗口的线程，从而欺骗windows。

实现：
原理：将显示欢迎窗体的线程作为Foreground的线程。
1. API函数的导入
public const int SW_HIDE = 0;
public const int SW_NORMAL = 1;
public const int SW_SHOWMINIMIZED = 2;
public const int SW_SHOWMAXIMIZED = 3;

[DllImport("User32.dll")]
public static extern void SetForegroundWindow(IntPtr hwnd);

[DllImport("User32.dll")]
public static extern IntPtr GetForegroundWindow();

[DllImport("User32.dll")]
public static extern int GetWindowThreadProcessId(IntPtr hwnd, IntPtr pProcId);

[DllImport("User32.dll")]
public static extern bool AttachThreadInput(int idAttach, int idAttachTo, int fAttach);

[DllImport("User32.dll")]
public static extern bool ShowWindowAsync(IntPtr hWnd, int cmdShow);

2. 使用API函数实现
private static void ActivateMainInstance(IntPtr mainWindowHandle, int foreId)
{
int curId = GetWindowThreadProcessId(mainWindowHandle, IntPtr.Zero);

if (curId != foreId)
{
AttachThreadInput(foreId, curId, 1);
SetForegroundWindow(mainWindowHandle);
AttachThreadInput(foreId, curId, 0);
}
else
{
SetForegroundWindow(mainWindowHandle);
}
ShowWindowAsync(mainWindowHandle, SW_SHOWMAXIMIZED);
}

3. 调用：
private static ApplicationContext _context = null;
private static SplashScreen _splash = null;
private static MainFrame _mForm = null;

private static void OnAppIdle(object sender, EventArgs e)
{
if (_context.MainForm == null)
{
Application.Idle -= new EventHandler(OnAppIdle);

// Initialize main frame and show
_mForm.InitializeFrame(); // 花时间点
_context.MainForm = _mForm;
_context.MainForm.Show();

// Active main form
ActivateMainInstance(_mForm.Handle, _splash.ThreadId);

// Close splash screen
_splash.Close();
_splash = null;
}
}

4. Main函数中：
// Show splash screen
_splash = new SplashScreen();
_splash.Run();

// Application running
_mForm = new MainFrame();
_context = new ApplicationContext();
Application.Idle += new EventHandler(OnAppIdle);
Application.Run(_context);

5. SplashScreen的实现：
public class SplashScreen
{
private SplashForm _sForm = null;
private Thread _workThread = null;

///

/// Thread function: shows this splash form.
///

private void Show()
{
_sForm = new SplashForm();
_sForm.ShowDialog();
}

///

/// Thread id property
///

public int ThreadId
{
get
{
return _workThread.ManagedThreadId;
}
}

///

/// Runs this instance.
///

public void Run()
{
_workThread = new Thread(new ThreadStart(Show));
_workThread.Start();
}

///

/// Closes this instance.
///

public void Close()
{
if (_sForm != null)
{
_sForm.HideSplash = true;
_workThread.Join();
_workThread = null;
}
}
}

This entry was posted on 星期四, 3月 8th, 2007 at 11:21 and is filed under 东东博客. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.