不能註冊爲的WinForms C＃

Question

這裏功率通知設置是代碼

[DllImport(@"User32", SetLastError = true, EntryPoint = "RegisterPowerSettingNotification", 
     CallingConvention = CallingConvention.StdCall)] 
    private static extern IntPtr RegisterPowerSettingNotification(IntPtr hRecipient, ref Guid PowerSettingGuid, Int32 Flags); 

    static Guid GUID_LIDSWITCH_STATE_CHANGE = new Guid(0xBA3E0F4D, 0xB817, 0x4094, 0xA2, 0xD1, 0xD5, 0x63, 0x79, 0xE6, 0xA0, 0xF3); 
    private const int DEVICE_NOTIFY_WINDOW_HANDLE = 0x00000000; 
    private const int WM_POWERBROADCAST = 0x0218; 
    const int PBT_POWERSETTINGCHANGE = 0x8013; 

    [StructLayout(LayoutKind.Sequential, Pack = 4)] 
    internal struct POWERBROADCAST_SETTING 
    { 
     public Guid PowerSetting; 
     public uint DataLength; 
     public byte Data; 
    } 

    private bool? _previousLidState = null; 


    public TrayIcon() 
    { 
     RegisterForPowerNotifications(); 

    } 

    [SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags = SecurityPermissionFlag.UnmanagedCode)] 
    protected override void WndProc(ref Message m) 
    { 
     switch (m.Msg) 
     { 
      case WM_POWERBROADCAST: 
       OnPowerBroadcast(m.WParam, m.LParam); 
       break; 
      default: 
       break; 
     } 
     base.WndProc(ref m); 
    } 


    private void RegisterForPowerNotifications() 
    { 
     IntPtr handle = this.Handle; 
     Debug.WriteLine("Handle: " + handle.ToString()); //If this line is omitted, then lastError = 1008 which is ERROR_NO_TOKEN, otherwise, lastError = 0 
     IntPtr hLIDSWITCHSTATECHANGE = RegisterPowerSettingNotification(handle, 
      ref GUID_LIDSWITCH_STATE_CHANGE, 
      DEVICE_NOTIFY_WINDOW_HANDLE); 
     Debug.WriteLine("Registered: " + hLIDSWITCHSTATECHANGE.ToString()); 
     Debug.WriteLine("LastError:" + Marshal.GetLastWin32Error().ToString()); 
    } 

    private void OnPowerBroadcast(IntPtr wParam, IntPtr lParam) 
    { 
     if ((int)wParam == PBT_POWERSETTINGCHANGE) 
     { 
      POWERBROADCAST_SETTING ps = (POWERBROADCAST_SETTING)Marshal.PtrToStructure(lParam, typeof(POWERBROADCAST_SETTING)); 
      IntPtr pData = (IntPtr)((int)lParam + Marshal.SizeOf(ps)); 
      Int32 iData = (Int32)Marshal.PtrToStructure(pData, typeof(Int32)); 
      if (ps.PowerSetting == GUID_LIDSWITCH_STATE_CHANGE) 
      { 
       bool isLidOpen = ps.Data != 0; 

       if (!isLidOpen == _previousLidState) 
       { 
        LidStatusChanged(isLidOpen); 
       } 

       _previousLidState = isLidOpen; 
      } 
     } 
    } 

    private void LidStatusChanged(bool isLidOpen) 
    { 
     if (isLidOpen) 
     { 
      //Do some action on lid open event 
      MessageBox.Show("Lid is now open"); 
     } 
     else 
     { 
      //Do some action on lid close event 
      MessageBox.Show("Lid is now closed"); 
     } 
    } 
} 
} 

我不知道是什麼問題。我打電話給WndProc功能，但蓋子關閉或打開時沒有任何反應。永遠不會調用LidStatusChanged。

我已按照this post但這並不能幫助所有匹配。

我不知道我做錯了什麼。所有的幫助非常感謝。

Answer 1

ShowInTaskbar = Visible = false; 

該錯誤在代碼片段中不再可見。導致問題的是ShowInTaskbar屬性分配。這是一個「困難」屬性，只能在傳遞給CreateWindowEx（）的樣式標誌中指定。所以這迫使Winforms銷燬當前窗口並創建一個新窗口，它現在得到一個不同的Handle值。沒有更多的通知。

您可能因爲試圖保持窗口不可見而陷入了麻煩。正確的方式做到這一點是：

protected override void SetVisibleCore(bool value) { 
    if (!IsHandleCreated) { 
     this.CreateHandle(); 
     value = false; 
    } 
    base.SetVisibleCore(value); 
} 

刪除的OnLoad（），不再需要，不叫，直到窗口實際上變得可見。而且，您要確保即使Handle值由於某種原因而更改（有幾個「困難」屬性），您仍然會收到通知。你可以通過從構造函數中刪除代碼和：

protected override void OnHandleCreated(EventArgs e) { 
    base.OnHandleCreated(e); 
    RegisterForPowerNotifications(); 
}