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         }