「檢測到CallbackOnCollectedDelegate」

Question

我試圖禁用Windows鍵。轉Bt基因在運行應用程序我得到一個錯誤「檢測CallbackOnCollectedDelegate」下面是我的代碼

Declare Function SetWindowsHookEx Lib "user32" Alias "SetWindowsHookExA" (ByVal idHook As Integer, ByVal lpfn As LowLevelKeyboardProcDelegate, ByVal hMod As IntPtr, ByVal dwThreadId As Integer) As IntPtr 
Declare Function UnhookWindowsHookEx Lib "user32" Alias "UnhookWindowsHookEx" (ByVal hHook As IntPtr) As Boolean 
Declare Function CallNextHookEx Lib "user32" Alias "CallNextHookEx" (ByVal hHook As IntPtr, ByVal nCode As Integer, ByVal wParam As Integer, ByRef lParam As KBDLLHOOKSTRUCT) As Integer 
Delegate Function LowLevelKeyboardProcDelegate(ByVal nCode As Integer, ByVal wParam As Integer, ByRef lParam As KBDLLHOOKSTRUCT) As Integer 

Const WH_KEYBOARD_LL As Integer = 13 

Structure KBDLLHOOKSTRUCT 
    Dim vkCode As Integer 
    Dim scanCode As Integer 
    Dim flags As Integer 
    Dim time As Integer 
    Dim dwExtraInfo As Integer 
End Structure 

Dim intLLKey As IntPtr 

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load 
    intLLKey = SetWindowsHookEx(WH_KEYBOARD_LL, AddressOf LowLevelKeyboardProc, IntPtr.Zero, 0) 
End Sub 

Private Sub Form1_FormClosing(sender As Object, e As FormClosingEventArgs) Handles MyBase.FormClosing 
    UnhookWindowsHookEx(intLLKey) 
End Sub 

Private Function LowLevelKeyboardProc(ByVal nCode As Integer, ByVal wParam As Integer, ByRef lParam As KBDLLHOOKSTRUCT) As Integer 
    Dim blnEat As Boolean = False 
    Select Case wParam 
     Case 256, 257, 260, 261 
      'Alt+Tab, Alt+Esc, Ctrl+Esc, Windows Key  
      blnEat = ((lParam.vkCode = 9) AndAlso (lParam.flags = 32)) Or 
      ((lParam.vkCode = 27) AndAlso (lParam.flags = 32)) Or 
      ((lParam.vkCode = 27) AndAlso (lParam.flags = 0)) Or 
      ((lParam.vkCode = 91) AndAlso (lParam.flags = 1)) Or 
      ((lParam.vkCode = 92) AndAlso (lParam.flags = 1)) 
    End Select 

    If blnEat = True Then 
     Return 1 
    Else 
     Return CallNextHookEx(IntPtr.Zero, nCode, wParam, lParam) 
    End If 
End Function 

任何幫助是非常讚賞

Answer 1

的問題是一樣的this post。不同之處在於他們使用C＃。但是，VB正在做同樣的事情;爲您生成一個委託。作爲參考，這是您的表單的Load事件中反編譯的代碼的樣子。

Private Sub Form1_Load(sender As Object, e As EventArgs) 
    Me.intLLKey = Form1.SetWindowsHookEx(13, New Form1.LowLevelKeyboardProcDelegate(Me.LowLevelKeyboardProc), IntPtr.Zero, 0) 
End Sub 

請注意，它正在爲您創建一個LowLevelKeyboardProcDelegate委託。我不會在這裏完全重複@HansPassant's answer，因爲他在描述問題和解決方案方面做得非常出色;只能說你需要存儲自己對LowLevelKeyboardProcDelegate委託的引用。