SetWindowsHookEx用于WM_MOUSEWHEEL

Question

我需要一个VB.NET代码示例，通过使用user32.dll和WM_MOUSEWHEEL的低级钩子捕获窗体外的鼠标滚轮滚动事件，就像Hans Passant在我其他问题的回答中所说的那样：Record mouse Middle button and wheel scroll。

以下是我需要实现的伪代码示例：

Dim mousewheel_up as boolean
Dim mousewheel_down as boolean

Sub that Overides the windows messages to set the mousewheel booleans

    If mousewheel_up then msgbox("MouseWheel up")
    If mousewheel_down then msgbox("MouseWheel down")

End sub

更新

我试过这个方法，但它只能在表单内工作，而且我不知道如何得到增量值：

   Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Application.AddMessageFilter(New MouseWheelMessageFilter())
    End Sub

Public Class MouseWheelMessageFilter : Implements IMessageFilter

    Public Function PreFilterMessage1(ByRef m As Message) As Boolean Implements IMessageFilter.PreFilterMessage

        ' Filter out WM_MOUSEWHEEL messages, which raise the MouseWheel event,
        ' whenever the Ctrl key is pressed. Otherwise, let them through.
        Const WM_MOUSEWHEEL As Integer = &H20A

        'If m.Msg = WM_MOUSEWHEEL & My.Computer.Keyboard.CtrlKeyDown Then
        If m.Msg = WM_MOUSEWHEEL Then
            ' Process the message here.
            If Form.ActiveForm IsNot Nothing Then
                MsgBox("Mouse scrolled!")
                ' TODO: Insert your code here to adjust the size of the active form.
                ' As shown above in the If statement, you can retrieve the form that
                ' is currently active using the static Form.ActiveForm property.
                ' ...
            End If
            Return True  ' swallow this particular message
        End If
        Return False    ' but let all other messages through
    End Function

End Class

- ElektroStudios

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这里有一个帖子，其中包含一些代码，应该可以满足你的需求。链接 - tinstaafl

Answer 1

你需要使用SetWindowsHookEx函数，并将钩子类型指定为*WH_MOUSE_LL*(14)。具有以下声明。

Public Structure Point
    Public X As Integer
    Public Y As Integer
End Structure

Public Structure Msllhookstruct
    Public Location As Point
    Public MouseData As Integer
    Public Flags As Integer
    Public Time As Integer
    Public ExtraInfo As Integer
End Structure

Private Delegate Function HookProc(nCode As Integer, wParam As Integer, ByRef lParam As Msllhookstruct) As Integer

<DllImport("user32.dll", SetLastError:=True)> _
Private Function SetWindowsHookEx(ByVal hookType As Integer, ByVal lpfn As HookProc, ByVal hMod As IntPtr, ByVal dwThreadId As UInteger) As IntPtr
End Function

<DllImport("user32.dll")> _
Private Function CallNextHookEx(ByVal hhk As IntPtr, ByVal nCode As Integer, ByVal wParam As IntPtr, ByRef lParam As Msllhookstruct) As IntPtr
End Function

Private Hook As IntPtr

在您的初始化程序中，请按如下方式使用它。

Hook = SetWindowsHookEx(14, AddressOf Proc, Process.GetCurrentProcess().MainModule.BaseAddress.ToInt32(), 0)

其中Proc是一个函数回调，如下所示：

Private Function Proc(nCode As Integer, wParam As Integer, ByRef lParam As Msllhookstruct) As IntPtr
    If wParam = 522 Then
        Dim Delta = CShort(lParam.MouseData >> 16)

        If Delta > 0 Then
            ' Up
        ElseIf Delta < 0 Then
            ' Down
        End If
    End If

    Return CallNextHookEx(Hook, nCode, wParam, lParam)
End Function

- ains

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你知道如何复制滚动吗？我的意思是如何向Windows发送消息以向上或向下滚动...？ - ElektroStudios

请查看SendInput。 - ains