VB编程动态注册ActiveX控件

在使用VB和其它一些Win9X下的编程软件，就要同ActiveX控件打交道，注册
和反注册控件是一件令人很头疼的事情。有时从网上下载了一个控件，但是在使用
时VB总是提示控件没有注册。又或者想删除一个控件却无法从注册中抹去。
实际上，每一个ActiveX控件都有两个输出函数：DllRegisterServer和
DllUnRegisterServer。顾名思义，通过这两个函数就可以注册和反注册控件了，
下面通过程序说明如何通过编程来注册。
首先在Form中加入两个CommandButton，不要改变它们的属性。然后在Form中
加入如下代码：
Private Declare Function RegComCtl32 Lib "ComCtl32.OCX" _
Alias "DllRegisterServer" () As Long
Private Declare Function UnRegComCtl32 Lib "ComCtl32.OCX" _
Alias "DllUnregisterServer" () As Long
Private Declare Function FormatMessage Lib "kernel32" _
Alias "FormatMessageA" (ByVal dwFlags As Long,_
lpSource As Any,ByVal dwMessageId As Long,_
ByVal dwLanguageId As Long,ByVal lpBuffer _
As String,ByVal nSize As Long,Arguments As _
Long) As Long
Private Declare Function GetLastError Lib "kernel32" () As Long

Const ERROR_SUCCESS = &H0

Private Sub Command1_Click()
Dim astr As String

'反注册ComCtl32.Ocx
If RegComCtl32 = ERROR_SUCCESS Then
MsgBox "注册成功"
Else
astr = String$(256,20)
FormatMessage FORMAT_MESSAGE_FROM_SYSTEM Or _
FORMAT_MESSAGE_IGNORE_INSERTS,0&,GetLastError,_
0&,astr,Len(astr),ByVal 0
MsgBox astr
End If
End Sub

Private Sub Command2_Click()
Dim astr As String

'反注册ComCtl32.Ocx
If UnRegComCtl32 = ERROR_SUCCESS Then
MsgBox "反注册成功"
Else
astr = String$(256,ByVal 0
MsgBox astr
End If
End Sub
运行程序，点击Command2反注册ComCtl32.Ocx控件，在VB菜单中选 Project|components
或按Ctrl+T，在控件列表框中可以看到已经没有ComCtl32.Ocx了。再运行程序，点击Command1
重新注册控件。
以上程序再VB5，WIN95下运行通过。

http://www.applevb.com/art/Control.txt