Pinvoke与GCC在VB.net 2010中编译的c++dll有关

编辑：很抱歉，我忘了你的目标是VB，不过你应该没有太大问题将我的代码翻译成它：D

以下对我有效：

using System;
using System.Runtime.InteropServices;
using System.Windows;
namespace WpfApplication3
{
    /// <summary>
    ///     Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            var intPtr = GetData();
            var ptrToStructure = Marshal.PtrToStructure<SCheatData>(intPtr);
        }
        [DllImport("mydll.dll")]
        private static extern IntPtr GetData();
        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
        public struct SCheat
        {
            public uint address;
            public byte byte1;
            public byte saved_byte;
            [MarshalAs(UnmanagedType.I1)] public bool enabled;
            [MarshalAs(UnmanagedType.I1)] public bool saved;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 22)] public string name;
        }
        [StructLayout(LayoutKind.Sequential)]
        public struct SCheatData
        {
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 150, ArraySubType = UnmanagedType.Struct)] public SCheat[]
                c;
            public uint num_cheats;
        }
    }
}

和：

// mydll.cpp : Defines the exported functions for the DLL application.
//
#include "stdafx.h"
typedef unsigned char      uint8_t;
typedef unsigned int       uint32_t;
#define MAX_CHEATS 150
struct SCheat
{
    uint32_t address;
    uint8_t byte1;
    uint8_t saved_byte;
    bool enabled;
    bool saved;
    char    name[22];
};
struct SCheatData
{
    struct SCheat c[MAX_CHEATS];
    uint32_t num_cheats;
};
extern "C" __declspec(dllexport) SCheatData* GetData()
{
    SCheatData* data = new SCheatData();
    data->num_cheats = MAX_CHEATS;
    for (size_t i = 0; i < MAX_CHEATS; i++)
    {
        SCheat c;
        c.address = 1234;
        c.byte1 = 0xAB;
        c.saved_byte = 0xCD;
        c.enabled = true;
        c.saved = true;
        strcpy(c.name, "abcdefghijklmnopqrstu");
        data->c[i] = c;
    }
    return data;
}

我使用了PInvoke互操作助手，它对生成签名很有帮助，也要小心Marshal.PtrToStructure的不同重载，因为并非所有风格都适用于任何情况。

好的，谢谢你的帮助，它做得不太好，但方向是我需要的答案。：）

代码修复。

C++标题：

__declspec(dllexport) int __cdecl S9xLoadCheatFile (const char *);
__declspec(dllexport) int __cdecl S9xSaveCheatFile (const char *);
__declspec(dllexport) SCheatData* __cdecl GetData();
struct SCheatData data1;

Dll.cpp:

SCheatData* __cdecl GetData()
{
   return &data1;
}

在保存和加载函数中直接与structdata1交互。

VB代码。

<StructLayoutAttribute(System.Runtime.InteropServices.LayoutKind.Sequential, CharSet:=CharSet.Ansi)> _
Public Structure SCheat
Public address As UInteger
Public byte1 As Byte
Public saved_byte As Byte
<MarshalAs(UnmanagedType.I1)> Public enabled As Boolean
<MarshalAs(UnmanagedType.I1)> Public saved As Boolean
<MarshalAs(UnmanagedType.ByValArray, SizeConst:=22, ArraySubType:=UnmanagedType.Struct)> Public name() As Char
End Structure
<StructLayoutAttribute(System.Runtime.InteropServices.LayoutKind.Sequential, CharSet:=CharSet.Ansi)> _
Public Structure SCheatData
<MarshalAs(UnmanagedType.ByValArray, SizeConst:=150)> Public c() As SCheat
Public num_cheats As UInteger
End Structure
<DllImport("c:minGWbinCheat_Functions.dll", CallingConvention:=CallingConvention.Cdecl)> _
Public Function _Z16S9xLoadCheatFilePKc(ByVal filename As String) As Integer
End Function
<DllImport("c:minGWbinCheat_Functions.dll", CallingConvention:=CallingConvention.Cdecl)> _
Public Function _Z7GetDatav() As IntPtr
End Function
Private sub try()
  Dim tryv As String = "C:\Users\Diane\Desktop\snes9x\Cheats\Super Mario World (U) [!].cht"
  Dim anotherP As New SCheatData
  MsgBox(_Z16S9xLoadCheatFilePKc(tryv))
  anotherP = System.Runtime.InteropServices.Marshal.PtrToStructure(_Z7GetDatav(), GetType(SCheatData))
  MsgBox(anotherP.num_cheats)
end sub

这适用于加载，从而验证结构是否正确。我认为这也适用于保存函数。至少我知道，如果我真的有问题，问题不会出在结构上。：）如果我在使用此保存功能时遇到问题，我会回复。

Edit，刚刚用System.Runtime.InteropServices.Marshal.StructeToPtr（anotherP，_Z7GetDatav，True）测试了反向，它成功了。所以我想我是做了一些正确定义结构的事情，而structuretoptr需要在dll中制作一个指针。要是我3天前知道这些事情就好了。谢谢你的帮助，尽管为了达到我的目的，我仍然需要把它弄得一团糟，但它给了我一个新的方向，这实际上很有帮助。

现在，我只需要为所有其他模拟器做同样的事情。哈哈。：）现在我有点明白了，应该不会花太长时间。