vb调用vc写的dll的问题又来了。：（ 还希望大家不吝赐教

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vc中函数原型
BOOL TV_GetSerial (char far *);
vb中声明
Private Declare Function TV_GetSerial Lib "usbid.dll" (ByRef Serial() As Byte) As Boolean
vb中调用
Dim Serial(1 To 20) As Byte
If itest.GetSerial(Serial()) <> 0 Then
MsgBox StrConv(Serial, vbUnicode)
End If

可却得到空值。。

谢谢大家来帮忙

[Caffy]

帮你up

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自己up一下

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If itest.GetSerial(Serial()) <> 0 Then
--> If TV_GetSerial(Serial()) <> 0 then

上面写错了

[rainstormmaster]

试试：

vb中声明
Private Declare Function TV_GetSerial Lib "usbid.dll" (byval Serial as long) As Boolean
vb中调用
Dim Serial(1 To 20) As Byte
dim i as long
i=GetSerial(varptr(Serial(1)))
If i> 0 Then
dim buff() as byte
redim buff(i-1)
copymemory buff(0),Serial(1),i
MsgBox StrConv(Serial, vbUnicode)
End If

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to:rainstormmaster(暴风雨 v2.0)
vc中函数原型
BOOL TV_GetSerial (char far *);

dim i as long
i=TV_GetSerial(varptr(Serial(1))) //根据vc中函数定义，得到的i值为0 或者1
If i> 0 Then
dim buff() as byte //
redim buff(i-1) //
copymemory buff(0),Serial(1),i //这几句要做什么呢？
//msdn：The CopyMemory function copies a block of memory
//from one location to another.

MsgBox StrConv(Serial, vbUnicode)
End If

[of123]

试试：
Private Declare Function TV_GetSerial Lib "usbid.dll" (ByRef Serial As Byte) As Boolean
vb中调用
Dim Serial(1 To 20) As Byte
If itest.GetSerial(Serial(1)) <> 0 Then
MsgBox StrConv(Serial, vbUnicode)
End If

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嘿嘿。我刚测试完。。
Dim Serial(1 To 20) As Byte
If itest.GetSerial(Serial(1)) <> 0 Then
MsgBox StrConv(Serial, vbUnicode)
End If

of123() 就写出正确答案了。。。佩服两位牛人。。

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看错了。of123()的代码稍微有点问题
声明处还是用 rainstormmaster(暴风雨 v2.0)
Private Declare Function TV_GetSerial Lib "usbid.dll" (byval Serial as long) As Boolean

如果用
Private Declare Function TV_GetSerial Lib "usbid.dll" (ByRef Serial As Byte) As Boolean
出现overflow错误

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非常感谢
of123()
rainstormmaster(暴风雨 v2.0)
这两天vb和vc之间调用的问题折腾我够戗。。。
请问有没有这方面的文档或者书可以系统的看一看？

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今天急性肠炎...去医院输液去了

[rainstormmaster]

我用copymemory的目的是取得字串，我假设你的函数的返回值是缓冲区内装载的字节数，但是看你的说明，copymemory就没必要用了

[visualvbjava]

Private Declare Function TV_GetSerial Lib "usbid.dll" (ByRef Serial As Byte) As Boolean