C#调用C++ Dll

现在项目基本都是旁边C++的哥们做好dll扔给我，然后我调用。好久之前晚上down了一份c#调用c++dll的方法，出处早已经遗忘。闲来无事，放上来好了。原作者看到后可以留言，我会把您链接放上的，帮了我很多！！！

 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
 using System.Reflection.Emit;
 using System.Runtime.InteropServices;
 using System.Text;
 
 namespace TEDS_App
 {
     public enum ModePass
     {
         ByValue = 0x0001,
         ByRef = 0x0002
     }
     public class FaultFunc
     {
         [DllImport("kernel32.dll")]
         static extern IntPtr LoadLibrary(string lpFileName);
         [DllImport("kernel32.dll")]
         static extern IntPtr GetProcAddress(IntPtr hModule, string lpProcName);
         [DllImport("kernel32", EntryPoint = "FreeLibrary", SetLastError = true)]
         static extern bool FreeLibrary(IntPtr hModule);
         private IntPtr hModule = IntPtr.Zero;
         private IntPtr farProc = IntPtr.Zero;
         public void LoadDll(string lpFileName)
         {
             hModule = LoadLibrary(lpFileName);
             if (hModule == IntPtr.Zero)
             {
                 throw (new Exception("没有找到：" + lpFileName + "."));
             }
         }
         public void LoadDll(IntPtr HMODULE)
         {
             if (HMODULE == IntPtr.Zero)
             {
                 throw (new Exception("所传入的函数库模块的句柄为空"));
             }
             hModule = HMODULE;
         }
         public void LoadFun(string lpProcName)
         {
             if (hModule == IntPtr.Zero)
             {
                 throw (new Exception("函数库模块的句柄为空，确保已进行加载dll操作"));
             }
             farProc = GetProcAddress(hModule, lpProcName);
             if (farProc == IntPtr.Zero)
             {
                 throw (new Exception("没有找到：" + lpProcName + "这个函数的入口点"));
             }
         }
         public void LoadFun(string lpFileName, string lpProcName)
         {
             hModule = LoadLibrary(lpFileName);
             if (hModule == IntPtr.Zero)
             {
                 throw (new Exception("没有找到：" + lpFileName + "."));
             }
             farProc = GetProcAddress(hModule, lpFileName);
             if (farProc == IntPtr.Zero)
             {
                 throw (new Exception("没有找到：" + lpProcName + "这个函数的入口点"));
             }
         }
         public void UnLoadDll()
         {
             FreeLibrary(hModule);
             hModule = IntPtr.Zero;
             farProc = IntPtr.Zero;
         }
         public object Invoke(object[] ObjArray_Parameter, Type[] TypeArray_parameterType, ModePass[] ModePassArray_Parameter, Type Type_Return)
         {
             if (hModule == IntPtr.Zero)
                 throw (new Exception("函数库模块的句柄为空，请确保进行了LoadLll操作"));
             if (farProc == IntPtr.Zero)
                 throw (new Exception("函数指针为空，请确保已进行LoadFun操作"));
             if (ObjArray_Parameter.Length != ModePassArray_Parameter.Length)
                 throw (new Exception("参数个数及其传递方式的个数不匹配"));
             AssemblyName MyAssemblyName = new AssemblyName();
             MyAssemblyName.Name = "InvokeFun";
             AssemblyBuilder MyAssemblyBuilder = AppDomain.CurrentDomain.DefineDynamicAssembly(MyAssemblyName, AssemblyBuilderAccess.Run);
             ModuleBuilder MyModuleBuilder = MyAssemblyBuilder.DefineDynamicModule("InvokeDll");
             MethodBuilder MyMethodBuilder = MyModuleBuilder.DefineGlobalMethod("FaultFun", MethodAttributes.Public | MethodAttributes.Static, Type_Return, TypeArray_parameterType);
             ILGenerator IL = MyMethodBuilder.GetILGenerator();
             int i;
             for (i = ; i < ObjArray_Parameter.Length; i++)
             {
                 switch (ModePassArray_Parameter[i])
                 {
                     case ModePass.ByValue:
                         IL.Emit(OpCodes.Ldarg, i);
                         break;
                     case ModePass.ByRef:
                         IL.Emit(OpCodes.Ldarga, i);
                         break;
                     default:
                         throw (new Exception("第" + (i + ).ToString() + "个参数没有给定正确的传递方式"));
                 }
             }
             if (IntPtr.Size == )
             {
                 IL.Emit(OpCodes.Ldc_I4, farProc.ToInt32());
             }
             else if (IntPtr.Size == )
             {
                 IL.Emit(OpCodes.Ldc_I8, farProc.ToInt64());
             }
             else
             {
                 throw new PlatformNotSupportedException();
             }
             IL.EmitCalli(OpCodes.Calli, CallingConvention.StdCall, Type_Return, TypeArray_parameterType);
             IL.Emit(OpCodes.Ret);
             MyModuleBuilder.CreateGlobalFunctions();
             MethodInfo MyMethodInfo = MyModuleBuilder.GetMethod("FaultFun");
             return MyMethodInfo.Invoke(null, ObjArray_Parameter);
         }
         public object Invoke(IntPtr IntPtr_Function, object[] ObjArray_Parameter, Type[] TypeArray_ParameterType, ModePass[] ModePassArray_Parameter, Type Type_Return)
         {
             if (hModule == IntPtr.Zero)
                 throw (new Exception("函数库模块的句柄为空，请确保已进行LoadDll操作"));
             if (IntPtr_Function == IntPtr.Zero)
                 throw (new Exception("函数指针IntPtr_Function为空"));
             farProc = IntPtr_Function;
             return Invoke(ObjArray_Parameter, TypeArray_ParameterType, ModePassArray_Parameter, Type_Return);
         }
     }
 
 }

一直以来，对于C++程序员报以崇高的敬意。。。一直觉得他们屌屌的，哈哈。

调用方式如下：

 PlusFunction.LoadDll(@"C:\win32dll.dll");//PlusFunction为调用类的实例
 PlusFunction.LoadFun("MyFun");
 byte[] a = File.ReadAllBytes(@"E:\19-bw\19-73.jpg");
 object[] Parameters = new object[] {a}; // 实参为a
 Type[] ParameterTypes = new Type[] { typeof(byte[])}; // 实参类型为byte[]
 ModePass[] themode = new ModePass[] {ModePass.ByValue}; // 传送方式为值传
 Type Type_Return = typeof(int); // 返回类型为int
 ret = (int)PlusFunction.Invoke(Parameters, ParameterTypes, themode, Type_Return);

其实，c++与c#主要的就是数据类型的对应了。简单点的还好说，稍微复杂的各种麻烦。。。关键是不好调试。

下面举些我用到的例子，以后遇到其他的再补充。日积月累- -

 c++                                    c#
 char*                                char[](string.tochararray)
 byte*                                 byte[]
 int                                    int
 int*                                    int[]
 结构体
 c++
 typedef struct SRectChange_TAG
 {
     //NV_RECT rect;
     int x;//左上角x轴坐标
     int y;//左上角y轴坐标
     int width;//宽
     int height;//高
     int degree;//报错级别；1最低，目前暂时设定3级
 }
 SRectChange;
 c#
 [StructLayout(LayoutKind.Sequential)]
 public struct SRectChange
 {
     public int x;
     public int y;
     public int width;
     public int height;
     public int degree;
 }
 结构体传递
 [DllImport("win32dll.dll", EntryPoint = "MyFun", CallingConvention = CallingConvention.Cdecl)]
 public static extern int MyFun(ref SRectChange rect, char[] str, char[] str2);
 c++结构体
 typedef struct
 {
     int osVersion;
     int majorVersion;
     int minorVersion;
     int buildNum;
     int platFormId;
     char szVersion[];
 }OSINFO;
 c#
 // OSINFO定义
 [StructLayout(LayoutKind.Sequential)]
 public struct OSINFO
 {
     public int osVersion;
     public int majorVersion;
     public int minorVersion;
     public int buildNum;
     public int platFormId;
     [MarshalAs(UnmanagedType.ByValTStr, SizeConst = )]
     public string szVersion;
 }  
 
 结构体数组传递
 c#代码
 [DllImport("win32dll.dll", EntryPoint = "MyFun", CallingConvention = CallingConvention.Cdecl)]
 public static extern int MyFun(IntPtr p, char[] str, char[] str2);
 数组传指针
 char[] newpic = ("").ToCharArray();
 char[] oldpic = ("").ToCharArray();
 SRectChange[] rects = new SRectChange[];
 for (int i = ; i < rects.Length; i++)
 {
     rects[i] = new SRectChange();
 }
 IntPtr[] ptArr = new IntPtr[];
 ptArr[] = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(SRectChange)) * ); //分配包含两个元素的数组
 IntPtr pt = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(SRectChange)));
 Marshal.Copy(ptArr, , pt, ); //拷贝指针数组
 MyFun(pt, newpic, oldpic);
 for (int i = ; i < ; i++)
 {
     rects[i] = (SRectChange)Marshal.PtrToStructure((IntPtr)(pt.ToInt32() + i * Marshal.SizeOf(typeof(SRectChange))), typeof(SRectChange));
     Console.WriteLine("x:{0} y:{1}", rects[i].x, rects[i].y);
 }

还说那句话：种一棵树最好的时间是十年前，其次是现在。