『.Net反射』ILGenerator.Emit 动态MSIL 编程 入门

转载请标明：舒小龙 http://www.cnblogs.com/shuxiaolong/articles/2924574.html

什么都不说，直接贴代码：

    class Program
    {
        static void Main(string[] args)
        {
            SetValue();
        }

        public static void SetValue()
        {
            int temp1 = 123;
            int temp2 = 234;
            int sum = temp1 + temp2;
            string sumStr = sum.ToString();

            Console.WriteLine(sumStr);
        }
    }

对应的 ILGenerator.Emit 代码：

 class Program
    {
        static void Main(string[] args)
        {
//.method public hidebysig static void  SetValue() cil managed
//{
//  // 代码大小       30 (0x1e)
//  .maxstack  2
//  .locals init ([0] int32 temp1,
//           [1] int32 temp2,
//           [2] int32 sum,
//           [3] string sumStr)
//  IL_0000:  nop
//  IL_0001:  ldc.i4.s   123
//  IL_0003:  stloc.0
//  IL_0004:  ldc.i4     0xea
//  IL_0009:  stloc.1
//  IL_000a:  ldloc.0
//  IL_000b:  ldloc.1
//  IL_000c:  add
//  IL_000d:  stloc.2
//  IL_000e:  ldloca.s   sum
//  IL_0010:  call       instance string [mscorlib]System.Int32::ToString()
//  IL_0015:  stloc.3
//  IL_0016:  ldloc.3
//  IL_0017:  call       void [mscorlib]System.Console::WriteLine(string)
//  IL_001c:  nop
//  IL_001d:  ret
//} // end of method Program::SetValue
            SetValue();
        }

        public static void SetValue()
        {
            DynamicMethod dm = new DynamicMethod("SetValueMethod", null, new Type[] { /*typeof(object), typeof(object)*/ }, true);

            ILGenerator generator = dm.GetILGenerator();

            generator.DeclareLocal(typeof(int));    //声明变量
            generator.DeclareLocal(typeof(int));    //声明变量
            generator.DeclareLocal(typeof(int));    //声明变量
            generator.DeclareLocal(typeof(string));    //声明变量

            //加载参数1，需要注意的是静态方法Ldarg_0对应的是参数1，
            //实例方法Ldarg_0对应的是this指针，Ldarg_1对应的是参数1，
            //即每个实例方法都传递一个隐含的this指针

            //int temp1 = 123;
            //int temp2 = 234;
            //int sum = temp1 + temp2;
            //string sumStr = sum.ToString();
            //Console.WriteLine(sumStr);

            //temp1 = 123
            generator.Emit(OpCodes.Ldc_I4, 123);
            generator.Emit(OpCodes.Stloc_0);

            //temp2 = 234
            generator.Emit(OpCodes.Ldc_I4, 234);
            generator.Emit(OpCodes.Stloc_1);

            //sum = temp1 + temp2
            generator.Emit(OpCodes.Ldloc_0);
            generator.Emit(OpCodes.Ldloc_1);
            generator.Emit(OpCodes.Add);
            generator.Emit(OpCodes.Stloc_2);

            //string sumStr = sum.ToString();
            //ldloca.s   sum
            //call       instance string [mscorlib]System.Int32::ToString()
            //stloc.3
            //调用成员函数
            generator.Emit(OpCodes.Ldloca_S, 2); //generator.Emit(OpCodes.Ldloc_2);
            MethodInfo toStringMethodInfo = typeof(Int32).GetMethod("ToString", new Type[] { });
            generator.Emit(OpCodes.Call, toStringMethodInfo);
            //generator.EmitCall(OpCodes.Call, toStringMethodInfo, null);   //和上面代码 同意思
            generator.Emit(OpCodes.Stloc_3);

            //Console.WriteLine(sumStr);
            //IL_0016:  ldloc.3
            //IL_0017:  call       void [mscorlib]System.Console::WriteLine(string)
            //调用静态函数
            generator.Emit(OpCodes.Ldloc_3);
            MethodInfo writeLineMethodInfo = typeof(Console).GetMethod("WriteLine", new Type[] { typeof(string) });
            generator.Emit(OpCodes.Call, writeLineMethodInfo);
            //generator.EmitCall(OpCodes.Call, writeLineMethodInfo, null);   //和上面代码 同意思

            //generator.Emit(OpCodes.Pop);   //是否是 无返回值函数 调用之后，不用弹出堆栈？

            //return
            generator.Emit(OpCodes.Ret);   //函数执行完成

            


            //将函数作为 委托
            VoidNoParamsMethod delegateMethod = (VoidNoParamsMethod)dm.CreateDelegate(typeof(VoidNoParamsMethod));
            //执行委托
            delegateMethod.Invoke();
        }


        public delegate void VoidNoParamsMethod();
    }

--------------------------------------------------------------------------

class Program
    {
        static void Main(string[] args)
        {
            TestClass testClass = new TestClass();
            testClass.Age = 1234;
            int age = testClass.Age;
            Console.WriteLine(age);
        }


         
    }

    public class TestClass
    {
        public int Age;
    }

对应的 ILGenerator.Emit 代码：

class Program
    {
        static void Main(string[] args)
        {
//.method private hidebysig static void  Main(string[] args) cil managed
//{
//  .entrypoint
//  // 代码大小       33 (0x21)
//  .maxstack  2
//  .locals init ([0] class ComplexSetValue.TestClass testClass,
//           [1] int32 age)
//  IL_0000:  nop
//  IL_0001:  newobj     instance void ComplexSetValue.TestClass::.ctor()
//  IL_0006:  stloc.0
//  IL_0007:  ldloc.0
//  IL_0008:  ldc.i4     0x4d2
//  IL_000d:  stfld      int32 ComplexSetValue.TestClass::Age
//  IL_0012:  ldloc.0
//  IL_0013:  ldfld      int32 ComplexSetValue.TestClass::Age
//  IL_0018:  stloc.1
//  IL_0019:  ldloc.1
//  IL_001a:  call       void [mscorlib]System.Console::WriteLine(int32)
//  IL_001f:  nop
//  IL_0020:  ret
//} // end of method Program::Main

            DynamicMethod dm = new DynamicMethod("SetValueMethod", null, new Type[] { /*typeof(object), typeof(object)*/ }, true);

            ILGenerator generator = dm.GetILGenerator();

            generator.DeclareLocal(typeof(TestClass));  //声明变量
            generator.DeclareLocal(typeof(int));  //声明变量

            //加载参数1，需要注意的是静态方法Ldarg_0对应的是参数1，
            //实例方法Ldarg_0对应的是this指针，Ldarg_1对应的是参数1，
            //即每个实例方法都传递一个隐含的this指针

            //TestClass testClass = new TestClass();
            //testClass.Age = 1234;
            //int age = testClass.Age;
            //Console.WriteLine(age);

            //TestClass testClass = new TestClass();
            //newobj     instance void ComplexSetValue.TestClass::.ctor()
            ConstructorInfo testClassConstructor = typeof (TestClass).GetConstructor(new Type[] {});
            generator.Emit(OpCodes.Newobj, testClassConstructor);
            generator.Emit(OpCodes.Stloc_0);

            //testClass.Age = 1234;
            //ldloc.0
            //ldc.i4     0x4d2  //1234
            //stfld      int32 ComplexSetValue.TestClass::Age
            generator.Emit(OpCodes.Ldloc_0);
            generator.Emit(OpCodes.Ldc_I4, 1234);
            FieldInfo fieldInfo = typeof (TestClass).GetField("Age");
            generator.Emit(OpCodes.Stfld, fieldInfo);

            //int age = testClass.Age;
            //ldloc.0
            //ldfld      int32 ComplexSetValue.TestClass::Age
            //stloc.1
            generator.Emit(OpCodes.Ldloc_0);
            generator.Emit(OpCodes.Ldfld, fieldInfo);
            generator.Emit(OpCodes.Stloc_1);

            //Console.WriteLine(age);
            //ldloc.0
            //call       void [mscorlib]System.Console::WriteLine(object)
            generator.Emit(OpCodes.Ldloc_1);
            MethodInfo writeLineMethodInfo = typeof(Console).GetMethod("WriteLine", new Type[] { typeof(int) });
            generator.Emit(OpCodes.Call, writeLineMethodInfo);
            //generator.EmitCall(OpCodes.Call, writeLineMethodInfo, null);   //和上面代码 同意思

            //generator.Emit(OpCodes.Pop);   //是否是 无返回值函数 调用之后，不用弹出堆栈？

            //return
            generator.Emit(OpCodes.Ret);   //函数执行完成


            //将函数作为 委托
            VoidNoParamsMethod delegateMethod = (VoidNoParamsMethod)dm.CreateDelegate(typeof(VoidNoParamsMethod));
            //执行委托
            delegateMethod.Invoke();
        }
    }

    public delegate void VoidNoParamsMethod();

    public class TestClass
    {
        public int Age;
    }