C#实现动态调用Windows DLL

部分代码来自于网络；废话不多说，上代码：

调用方法：

object obj = WinDllInvoke("Kernel32.dll", "Beep", new object[] { 750, 300 }, typeof(void));

 

函数代码：

 1 [System.Runtime.InteropServices.DllImport("kernel32" )]
 2         private static extern IntPtr LoadLibrary(string  lpLibFileName);
 3 
 4         [System.Runtime.InteropServices.DllImport("kernel32" )]
 5         private static extern IntPtr GetProcAddress(IntPtr hModule, string  lpProcName);
 6 
 7         [System.Runtime.InteropServices.DllImport("kernel32" )]
 8         private static extern  IntPtr FreeLibrary(IntPtr hLibModule);
 9 
10         /// <summary>
11         ///  动态调用Windows DLL
12         /// </summary>
13         /// <param name="fileName">Dll文件名</param>
14         /// <param name="funName">待调用的函数名</param>
15         /// <param name="objParams">函数参数</param>
16         /// <param name="returnType">返回值</param>
17         /// <returns>调用结果</returns>
18         private static object WinDllInvoke(string fileName, string funName, object [] objParams, Type returnType)
19          {
20             IntPtr libHandle =  IntPtr.Zero;
21 
22             try
23              {
24                 //获取函数地址
25                 libHandle =  LoadLibrary(fileName);
26                 if (libHandle == IntPtr.Zero) return null ;
27                 IntPtr procAddres =  GetProcAddress(libHandle, funName);
28                 if (procAddres == IntPtr.Zero) return null ;
29                  
30                 //获取参数类型
31                 Type[] paramTypes = new  Type[objParams.Length];
32                 for (int i = 0; i < objParams.Length; ++ i)
33                  {
34                     paramTypes[i] =  objParams[i].GetType();
35                  }
36 
37                 //构建调用方法模型
38                 AssemblyName asembyName = new  AssemblyName();
39                 asembyName.Name = "WinDllInvoke_Assembly" ;
40                 AssemblyBuilder asembyBuilder =  AppDomain.CurrentDomain.DefineDynamicAssembly(asembyName, AssemblyBuilderAccess.Run);
41                 ModuleBuilder moduleBuilder = asembyBuilder.DefineDynamicModule("WinDllInvoke" );
42                 MethodBuilder methodBuilder = moduleBuilder.DefineGlobalMethod("InvokeFun", MethodAttributes.Public |  MethodAttributes.Static, returnType, paramTypes);
43 
44                 //获取一个 ILGenerator ，用于发送所需的 IL 
45                 ILGenerator IL =  methodBuilder.GetILGenerator();
46                 for (int j = 0; j < paramTypes.Length; ++ j)
47                  {
48                     //将参数压入堆栈
49                     if  (paramTypes[j].IsValueType)
50                      {
51                         IL.Emit(OpCodes.Ldarg, j); //By Value
52                      }
53                     else
54                      {
55                         IL.Emit(OpCodes.Ldarga, j); //By Addrsss
56                      }
57                  }
58 
59                 // 判断处理器类型
60                 if (IntPtr.Size == 4 )
61                  {
62                      IL.Emit(OpCodes.Ldc_I4, procAddres.ToInt32());
63                  }
64                 else if (IntPtr.Size == 8 )
65                  {
66                      IL.Emit(OpCodes.Ldc_I8, procAddres.ToInt64());
67                  }
68                 else
69                  {
70                     throw new PlatformNotSupportedException("不好意思，偶不认得你哦！" );
71                  }
72 
73                  IL.EmitCalli(OpCodes.Calli, CallingConvention.StdCall, returnType, paramTypes);
74                 IL.Emit(OpCodes.Ret); // 返回值 
75                  moduleBuilder.CreateGlobalFunctions();
76 
77                 // 取得方法信息 
78                 MethodInfo methodInfo = moduleBuilder.GetMethod("InvokeFun" );
79 
80                 return methodInfo.Invoke(null, objParams);// 调用方法，并返回其值
81              }
82             catch { return null ; }
83             finally
84              {
85                 if (libHandle != IntPtr.Zero) FreeLibrary(libHandle); //释放资源
86              }
87         }