学步园

 编写钩子程序时，在代码：

hHook = SetWindowsHookEx(WH_MOUSE_LL, AddressOf HookProc, App.hInstance, 0)

处出现错误，提示'AddressOf' expression cannot be converted to 'Long' because 'Long' is not a delegate type.

SetWindowsHookEx的原来的定义如下：

 Private Declare Function SetWindowsHookEx Lib "user32" _<br /> Alias "SetWindowsHookExA" (ByVal idHook As Long, ByVal _<br /> lpfn As Long, ByVal hmod As Long, ByVal dwThreadId As _<br /> Long) As Long<br />

于是我新定义了一个和HookProc一样的函数：

Public Delegate Function HookProcBase(ByVal nCode As Long, ByVal wParam As Long, ByVal lparam As Long) As Long

然后把SetWindowsHookEx改为：

Public Declare Function SetWindowsHookEx Lib "user32" _<br /> Alias "SetWindowsHookExA" (ByVal idHook As Long, _<br /> ByVal lpfn As HookProcBase, ByVal hmod As Long, ByVal _<br /> dwThreadID As Long) As Long

这样就没有问题了。