vb.net 调用vc++ 含有结构体的dll出错
最近遇到vb.net 要调用vc++写的含有结构体的dll，调试老报错。郁闷死了，向高手求救。vc++的dll及结构体结构是：
struct nc_userinfo {
char username[21];
char password[15];
UINT dataaccess
}
struct nc_appinfo{
char appname[256];
UINT kind
}
int nc_app3( HWND hWnd, UINT* logonid, nc_appinfo* appinfo, nc_userinfo* usrinfo, char* accessfile, int* info1)
我的vb.net是这样调用的：
Imports System.Runtime.InteropServices
<StructLayoutAttribute(LayoutKind.Sequential, CharSet:=CharSet.Ansi)> _
Public Structure nc_appinfo
<MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst:=256)> _
Public appname As String
Public kind As UInteger
End Structure
<StructLayoutAttribute(LayoutKind.Sequential, CharSet:=CharSet.Ansi)> _
Public Structure nc_userinfo
<MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst:=NC_USER_NAME)> _
Public username As String
<MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst:=NC_PASSWORD)> _
Public password As String
Public dataaccess As UInteger
End Structure
<DllImport("mydll", EntryPoint:="nc_app3", CallingConvention:=CallingConvention.Cdecl)> _
Public Function nc_app_start(ByRef hWnd As System.IntPtr, _
ByRef logonid As UInteger, _
ByRef appinfo As nc_appinfo, _
ByRef usrinfo As nc_userinfo, _
ByRef accessfile As String, _
ByRef info1 As Integer) As Integer
End Function
调试时老报“System.AccessViolationException”类型的未经处理的异常出现在 mscorlib.dll 中
其他信息: 尝试读取或写入受保护的内存。这通常指示其他内存已损坏。
vb.net vc++ dll structure --------------------编程问答--------------------
<StructLayoutAttribute(LayoutKind.Sequential, CharSet:=CharSet.Ansi)> _--------------------编程问答-------------------- gxingmin ，试了，不行 --------------------编程问答-------------------- try
Public Structure nc_appinfo
<MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst:=256)> _
Public appname() As byte
Public kind As UInteger
End Structure
<StructLayoutAttribute(LayoutKind.Sequential, CharSet:=CharSet.Ansi)> _
Public Structure nc_userinfo
<MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst:=21)> _
Public username() As byte
<MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst:=15)> _
Public password() As byte
Public dataaccess As UInteger
End Structure
<DllImport("mydll", EntryPoint:="nc_app3", CallingConvention:=CallingConvention.Cdecl)> _
Public Function nc_app_start(ByRef hWnd As System.IntPtr, _
ByRef logonid As UInteger, _
ByRef appinfo As nc_appinfo, _
ByRef usrinfo As nc_userinfo, _
ByRef accessfile As String, _
ByRef info1 As IntPtr) As Integer --------------------编程问答-------------------- 主要是要看c++怎么调用的？
--------------------编程问答-------------------- 我刚刚用vb6调用该dll成功了，其中用到vbanycall这个类模块（可以调cdecl的dllaccessfile As String).
vb.net还在测试。
vb6用了十几年，还是能解决一些问题。
不过，我还得想办法搞定vb.net。
重新检查了vb.net代码，发现问题可能处在accessfile As String上，应该改为accessfile As bybe.
--------------------编程问答-------------------- 终于自己搞定了没有报警了，accessfile 为一个单字符故定义为char
跟大家分享一下：
--------------------编程问答-------------------- 既然vb.net有char数据类型，那咱就用上。更准确地方法是：
Imports System.Runtime.InteropServices
'删除该行<StructLayoutAttribute(LayoutKind.Sequential, CharSet:=CharSet.Ansi)>
Public Structure nc_appinfo
<MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst:=256)> _
Public appname As String
Public kind As UInteger
End Structure
'删除该行 [color=#FF0000]<StructLayoutAttribute(LayoutKind.Sequential, CharSet:=CharSet.Ansi)>
Public Structure nc_userinfo
<MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst:=NC_USER_NAME)> _
Public username As String
<MarshalAsAttribute(UnmanagedType.ByValTStr, SizeConst:=NC_PASSWORD)> _
Public password As String
Public dataaccess As UInteger
End Structure
<DllImport("mydll", EntryPoint:="nc_app3", CallingConvention:=CallingConvention.Cdecl)> _
Public Function nc_app_start(ByRef hWnd As System.IntPtr, _
ByRef logonid As UInteger, _
ByRef appinfo As nc_appinfo, _
ByRef usrinfo As nc_userinfo, _
ByRef accessfile As char, _
ByRef info1 As Integer) As Integer
End Function
Imports System.Runtime.InteropServices
<StructLayoutAttribute(LayoutKind.Sequential, CharSet:=CharSet.Ansi)> _
Public Structure nc_appinfo
<MarshalAsAttribute(UnmanagedType.ByValArray, SizeConst:=256)> _
Public appname() As Char
Public kind As UInteger
End Structure
<StructLayoutAttribute(LayoutKind.Sequential, CharSet:=CharSet.Ansi)> _
Public Structure nc_userinfo
<MarshalAsAttribute(UnmanagedType.ByValArray, SizeConst:=NC_USER_NAME)> _
Public username() As Char
<MarshalAsAttribute(UnmanagedType.ByValArray, SizeConst:=NC_PASSWORD)> _
Public password() As Char
Public dataaccess As UInteger
End Structure
<DllImport("mydll", EntryPoint:="nc_app3", CallingConvention:=CallingConvention.Cdecl)> _
Public Function nc_app_start(ByRef hWnd As System.IntPtr, _
ByRef logonid As UInteger, _
ByRef appinfo As nc_appinfo, _
ByRef usrinfo As nc_userinfo, _
ByRef accessfile As Char, _
ByRef info1 As Integer) As Integer
End Function
补充：.NET技术 , VB.NET
