VBA调用DLL，及处理C语言的【char*】类型参数

DLL导出函数定义

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 __declspec(dllexport) int __stdcall MyExportFunction(const char * p1, const char * p2, char * const  out);

 

VBA处理（VB.net的处理也类似）

要注意的一点是，C语言中的【char *】类型相当于VBA（或VB.NET）中的【ByRef  aa As Byte】 。

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Private Declare Function fnc Lib "DLL路径\DLL名.dll" _   

Alias "函数名" (ByRef p1 As Byte, ByRef p2 As Byte, ByRef out As Byte) As Integer

 

Sub Test()   

    Dim pUserID() As Byte   

    '字符串转换为Byte数组 

    Call ToBytes("999999900", pUserID)

    Dim pYYMMDD() As Byte
    Call ToBytes("091020", pYYMMDD)

    Dim pPWD(50) As Byte

 

    aa = fnc(pUserID(0), pYYMMDD(0), pPWD(0))
       
    Dim str As String
    str = StrConv(pPWD, vbUnicode)
   
    MsgBox (str)
   
End Sub

'字符串转换为Byte数组
Private Sub ToBytes(ByRef src As String, ByRef dst() As Byte)

    ReDim dst(Len(src))

    Dim i As Integer
    For i = 1 To Len(src)
        dst(i - 1) = Asc(Mid(src, i, 1))
    Next

End Sub