VB.NET RaiseEvent请求表达式

Question

我正在学习VB.NET中的键盘钩子，需要帮助解决一个错误。起初，它告诉我必须将(Not (KeyDown) Is Nothing) & KeyUp更改为RaiseEvent，因为它们是事件，我已经这样做了。但是现在它告诉我应该有一个')‘表达式，而我不知道这是什么意思。我已经使用VB.NET维基和代码片段走到了这一步，我为自己感到非常自豪。我现在不希望这件事失败。请帮帮我！在最底部有一张错误的图像。

    Public Event KeyDown As KeyboardHookCallback

    Public Event KeyUp As KeyboardHookCallback
Private Function HookFunc(ByVal nCode As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As IntPtr
        If (nCode >= 0) Then
            Dim iwParam As Integer = wParam.ToInt32
            If ((iwParam = WM_KEYDOWN) _
        OrElse (iwParam = WM_SYSKEYDOWN)) Then
                If (Not RaiseEvent KeyDown Is Nothing) Then
                    RaiseEvent KeyDown(CType(Marshal.ReadInt32(lParam), VKeys))
                End If

            End If

            If ((iwParam = WM_KEYUP) _
    OrElse (iwParam = WM_SYSKEYUP)) Then
                If (Not RaiseEvent KeyUp Is Nothing) Then
                    RaiseEvent KeyUp(CType(Marshal.ReadInt32(lParam), VKeys))
                End If

            End If

        End If

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

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