Question

我正在努力学习键盘挂钩是如何工作的并且失败了。我收集了以下代码，其中包含了我想要的一些内容我要做的是拦截某些键盘输入并执行我的代码，而不是将这些特定的键盘输入传递回应用程序。我的代码能够拦截键盘输入并执行我的代码，但键盘输入总是在我的代码执行后传递给应用程序。有什么建议吗？

Imports System
Imports System.Runtime.CompilerServices
Imports System.Runtime.InteropServices
Imports System.Windows.Forms


Friend Class KeyboardHooking
' Methods
<DllImport("user32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _
Private Shared Function CallNextHookEx(ByVal hhk As IntPtr, ByVal nCode As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As IntPtr
End Function

<DllImport("kernel32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _
Private Shared Function GetModuleHandle(ByVal lpModuleName As String) As IntPtr
End Function

Private Shared Function HookCallback(ByVal nCode As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As Integer
    If ((nCode >= 0) AndAlso (nCode = 0)) Then
        Dim keyData As Keys = DirectCast(CInt(wParam), Keys)

        If ((BindingFunctions.IsKeyDown(Keys.ControlKey) AndAlso BindingFunctions.IsKeyDown(Keys.ShiftKey)) AndAlso BindingFunctions.IsKeyDown(My.Settings.keyLinkQuickToDB)) Then
            linkQuickToDB()

        'Qty Changer
        ElseIf ((BindingFunctions.IsKeyDown(Keys.ControlKey) AndAlso BindingFunctions.IsKeyDown(Keys.ShiftKey)) AndAlso BindingFunctions.IsKeyDown(My.Settings.keyQtyChange)) Then
            qtyChanger()
        End If
    End If

    Return CInt(KeyboardHooking.CallNextHookEx(KeyboardHooking._hookID, nCode, wParam, lParam))

End Function

Public Shared Sub ReleaseHook()
    KeyboardHooking.UnhookWindowsHookEx(KeyboardHooking._hookID)
End Sub

Public Shared Sub SetHook()
    KeyboardHooking._hookID = KeyboardHooking.SetWindowsHookEx(2, KeyboardHooking._proc, IntPtr.Zero, Convert.ToUInt32(AppDomain.GetCurrentThreadId))
End Sub

<DllImport("user32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _
Private Shared Function SetWindowsHookEx(ByVal idHook As Integer, ByVal lpfn As LowLevelKeyboardProc, ByVal hMod As IntPtr, ByVal dwThreadId As UInt32) As IntPtr
End Function

<DllImport("user32.dll", CharSet:=CharSet.Auto, SetLastError:=True)> _
Private Shared Function UnhookWindowsHookEx(ByVal hhk As IntPtr) As <MarshalAs(UnmanagedType.Bool)> Boolean
End Function


' Fields
Private Shared _hookID As IntPtr = IntPtr.Zero
Private Shared _proc As LowLevelKeyboardProc = New LowLevelKeyboardProc(AddressOf KeyboardHooking.HookCallback)
Private Const WH_KEYBOARD As Integer = 2
Private Const WH_KEYBOARD_LL As Integer = 13
Private Const WM_KEYDOWN As Integer = &H100

' Nested Types
Public Delegate Function LowLevelKeyboardProc(ByVal nCode As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As Integer

End Class

Public Class BindingFunctions
' Methods
<DllImport("user32.dll")> _
Private Shared Function GetKeyState(ByVal nVirtKey As Integer) As Short
End Function

Public Shared Function IsKeyDown(ByVal keys As Keys) As Boolean
    Return ((BindingFunctions.GetKeyState(CInt(keys)) And &H8000) = &H8000)
End Function

End Class

Answer 1

在回调函数中返回非零值。

Private Shared Function HookCallback(ByVal nCode As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As Integer
    If ((nCode >= 0) AndAlso (nCode = 0)) Then
        Dim keyData As Keys = DirectCast(CInt(wParam), Keys)

        If ((BindingFunctions.IsKeyDown(Keys.ControlKey) AndAlso BindingFunctions.IsKeyDown(Keys.ShiftKey)) AndAlso BindingFunctions.IsKeyDown(My.Settings.keyLinkQuickToDB)) Then
            linkQuickToDB()
            Return -1 'prevent passing

        'Qty Changer
        ElseIf ((BindingFunctions.IsKeyDown(Keys.ControlKey) AndAlso BindingFunctions.IsKeyDown(Keys.ShiftKey)) AndAlso BindingFunctions.IsKeyDown(My.Settings.keyQtyChange)) Then
            qtyChanger()
            Return -1 'prevent passing
        End If
    End If

    Return CInt(KeyboardHooking.CallNextHookEx(KeyboardHooking._hookID, nCode, wParam, lParam))    
End Function

更多细节 http://msdn.microsoft.com/en-us/library/windows/desktop/ms644984(v=vs.85).aspx

键盘挂钩，防止键盘输入到应用程序

1 个答案: