求助，在线等待！

'这段代码用来实现这样一功能:比如说我在Combo1中输入了一个文本
'则A数组中含有这个文本的项目都自动显示出来.
'这一点有点象VB自带的那个API浏览器一样,输入函数名称,就会自动显示并选中该函数名称.
'现在我遇到了问题,看不到效果.
'哪位高手帮忙看一下这个代码,找找BUG啊!
'或者给我一个类似于API浏览器的代码一下也行,
'不过我是要在ComboBox中实现象API浏览器一样的效果
'急!!!!!!!


Dim Temp As String
Dim A(3) As String
Private Const CB_SHOWDROPDOWN = &H14F
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 Sub Combo1_Change()
On Error Resume Next
Dim I As Integer

A(0) = "dsfs"
A(1) = "dsaf"
A(2) = "fb"
A(3) = "bgsd"
Temp = UCase(Combo1.Text)

For I = 0 To 3
If InStr(1, A(I), Temp) <> 0 Then
Combo1.AddItem A(I)
End If
SendMessage Combo1.hwnd, CB_SHOWDROPDOWN, True, 0
Next I
End Sub