调用系统api函数

调用系统user32.dll的一个窗口函数,结果为弹出一个提示框

Declare Auto Function MBox Lib "user32.dll" Alias "MessageBox" ( '声明

ByVal hWnd As Integer,

ByVal txt As String,

ByVal caption As String,

ByVal Typ As Integer) As Integer

Private Sub Form5_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

Const MB_ICONQUESTION As Integer = &H20 '定义常量

Const MB_YESNO As Integer = &H4

Const IDYES As Integer = 6

Const IDNO As Integer = 7

' Stores the return value.

Dim RetVal As Integer

RetVal = MBox(0, "Declare DLL Test", "Windows API MessageBox",MB_ICONQUESTION Or MB_YESNO)

If RetVal = IDYES Then

MsgBox("You chose Yes")

Else

MsgBox("You chose No")

End If

End Sub