当当前活动窗口发生变化时,如何调用回调。我已经看到了如何使用CBTProc完成它。但是,全局事件不容易与托管代码挂钩。我有兴趣找到一种不需要轮询的方法。我更喜欢事件驱动的方法。
此致
答案 0 :(得分:52)
创建一个新的Windows窗体项目,添加一个文本框,使其成为多行,并设置要填充的文本框Dock属性,将其命名为Log并粘贴到以下代码中(您需要将System.Runtime.InteropServices添加到您的usings)...
WinEventDelegate dele = null;
public Form1()
{
InitializeComponent();
dele = new WinEventDelegate(WinEventProc);
IntPtr m_hhook = SetWinEventHook(EVENT_SYSTEM_FOREGROUND, EVENT_SYSTEM_FOREGROUND, IntPtr.Zero, dele, 0, 0, WINEVENT_OUTOFCONTEXT);
}
delegate void WinEventDelegate(IntPtr hWinEventHook, uint eventType, IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime);
[DllImport("user32.dll")]
static extern IntPtr SetWinEventHook(uint eventMin, uint eventMax, IntPtr hmodWinEventProc, WinEventDelegate lpfnWinEventProc, uint idProcess, uint idThread, uint dwFlags);
private const uint WINEVENT_OUTOFCONTEXT = 0;
private const uint EVENT_SYSTEM_FOREGROUND = 3;
[DllImport("user32.dll")]
static extern IntPtr GetForegroundWindow();
[DllImport("user32.dll")]
static extern int GetWindowText(IntPtr hWnd, StringBuilder text, int count);
private string GetActiveWindowTitle()
{
const int nChars = 256;
IntPtr handle = IntPtr.Zero;
StringBuilder Buff = new StringBuilder(nChars);
handle = GetForegroundWindow();
if (GetWindowText(handle, Buff, nChars) > 0)
{
return Buff.ToString();
}
return null;
}
public void WinEventProc(IntPtr hWinEventHook, uint eventType, IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime)
{
Log.Text += GetActiveWindowTitle() + "\r\n";
}
答案 1 :(得分:17)
我知道这个帖子很旧,但是为了将来使用: 运行代码时,你会发现一段时间后崩溃。这是由Form构造函数中的行引起的:
public Form1()
{
InitializeComponent();
WinEventDelegate dele = new WinEventDelegate(WinEventProc);//<-causing ERROR
IntPtr m_hhook = SetWinEventHook(EVENT_SYSTEM_FOREGROUND, EVENT_SYSTEM_FOREGROUND, IntPtr.Zero, dele, 0, 0, WINEVENT_OUTOFCONTEXT);
}
而不是上述内容进行以下修改:
public Form1()
{
InitializeComponent();
dele = new WinEventDelegate(WinEventProc);
IntPtr m_hhook = SetWinEventHook(EVENT_SYSTEM_FOREGROUND, EVENT_SYSTEM_FOREGROUND, IntPtr.Zero, dele, 0, 0, WINEVENT_OUTOFCONTEXT);
}
WinEventDelegate dele = null;
..现在按预期工作!
答案 2 :(得分:7)
您可以使用SetWinEventHook
并收听EVENT_SYSTEM_FOREGROUND
事件。使用WINEVENT_OUTOFCONTEXT
标志可以避免全局挂钩问题。