从VB5迁移到VB.NET时遇到了USB .dll调用问题。

Question

我正在尝试与使用FDTI 232RL的usb设备通信。我已经安装了驱动程序并将.dll调用集成到我的VB5代码中，它工作得很好。我想让它在VB.net上工作，但我得到了PInvokeStackImballance错误消息。在VB5中，我有以下代码序列：

Private Declare Function FT_ListDevices Lib "FTD2XX.DLL" (ByVal arg1 As Long, ByVal arg2 As String, ByVal dwFlags As Long) As Long
...
Dim strSerialNumber As String * 256
...
LoggerList.AddItem ("ListDevices by S/N")
If FT_ListDevices(0, strSerialNumber, FT_LIST_BY_INDEX Or FT_OPEN_BY_SERIAL_NUMBER) <> FT_OK Then
...

在VB.NET中：

Private Declare Function FT_ListDevices Lib "FTD2XX.DLL" (ByVal arg1 As Long, ByVal arg2 As String, ByVal dwFlags As Long) As Long
...
Dim strSerialNumber As Stringbuilder new = stringbuilder (" ",256)
...
LoggerList.AddItem ("ListDevices by S/N")
If FT_ListDevices(0, strSerialNumber, FT_LIST_BY_INDEX Or FT_OPEN_BY_SERIAL_NUMBER) <> FT_OK Then
...

错误发生在if语句中。是否需要使用import("FTD2XX.dll")导入Dll？我也尝试过Dim strSerialNumber(256) as char，但也不起作用。我是不是解决错了问题？

Answer 1

在VB5中，long是32位，而在VB.Net中是64位。将函数中的参数从long更改为int (在VB.Net上为32位)。

Private Declare Function FT_ListDevices Lib "FTD2XX.DLL" (ByVal arg1 As Integer, _
        ByVal arg2 As String, ByVal dwFlags As Integer) As Integer