Question

VB中 ComboBox控件如何屏蔽鼠标滚轮事件

我在使用ComboBox控件时，先选择ComboBox控件中的某一项，然后可以滑动鼠标滚轮改变选择的项，现在我想屏蔽掉这功能

Answer 1

在combox选择完成后的位置添加代码，把焦点转移，如移到某个控件上 ***.setfocus

Answer 2

'模块中：
Option Explicit
Private Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Private Declare Function CallWindowProc Lib "user32" Alias "CallWindowProcA" (ByVal lpPrevWndFunc As Long, ByVal hwnd As Long, ByVal msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Private Const WM_MOUSEWHEEL As Long = &H20A
Private Const GWL_WNDPROC = (-4)
Private PrevWndProc As Long

Public Function SubWndProc(ByVal hwnd As Long, ByVal msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Select Case msg '在这里进行过滤.如果知道其他的消息,也可以在这里过滤.
Case WM_MOUSEWHEEL
SubWndProc = 1 '屏蔽掉
Exit Function
End Select
SubWndProc = CallWindowProc(PrevWndProc, hwnd, msg, wParam, lParam) '其它消息不管
End Function
Public Sub CallHook(ByVal hwnd As Long)
PrevWndProc = SetWindowLong(hwnd, GWL_WNDPROC, AddressOf SubWndProc)
End Sub
Public Sub CallUnhook(ByVal hwnd As Long)
Dim lngReturnValue As Long
lngReturnValue = SetWindowLong(hwnd, GWL_WNDPROC, PrevWndProc)
End Sub
'窗体中：
Private Sub Form_Load()
Dim i As Integer
CallHook Combo1.hwnd
For i = 1 To 10
Combo1.AddItem i
Next
End Sub

Private Sub Form_Unload(Cancel As Integer)
CallUnhook Combo1.hwnd
End Sub

追问

能具体说下这代码的执行吗？

追答

这段是win消息hook，通过截获windows的滚轮消息，来屏蔽。
具体什么是hook，在百度搜索，就知道了

追问

还是不懂，大神能具体的说下每段代码的作用吗？

追答

Public Function SubWndProc(ByVal hwnd As Long, ByVal msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long'回调函数，用来截获windows消息,
Select Case msg '在这里进行过滤.如果知道其他的消息,也可以在这里过滤.
Case WM_MOUSEWHEEL'WM_MOUSEWHEEL是滚轮转动时就产生这个消息
SubWndProc = 1 '屏蔽掉
Exit Function
End Select
SubWndProc = CallWindowProc(PrevWndProc, hwnd, msg, wParam, lParam) '其它消息不管，没有这一句，就影响到其它消息了
End Function
Public Sub CallHook(ByVal hwnd As Long)'设置消息hook（也叫钩子）
PrevWndProc = SetWindowLong(hwnd, GWL_WNDPROC, AddressOf SubWndProc)
End Sub
Public Sub CallUnhook(ByVal hwnd As Long)'退出前必须卸哉
Dim lngReturnValue As Long
lngReturnValue = SetWindowLong(hwnd, GWL_WNDPROC, PrevWndProc)
End Sub