c# - 动态使用运行时编译的程序集

Question

我从代码动态编译代码:

            string code = @"
                namespace CodeInjection
                {
                    public static class DynConcatenateString
                    {
                        public static string Concatenate(string s1, string s2){
                            return s1 + "" ! "" + s2;
                        }
                    }
                }";

            // http://stackoverflow.com/questions/604501/generating-dll-assembly-dynamically-at-run-time
            Console.WriteLine("Now doing some injection...");

            Console.WriteLine("Creating injected code in memory");


            CSharpCodeProvider codeProvider = new CSharpCodeProvider();
            ICodeCompiler icc = codeProvider.CreateCompiler();
            CompilerParameters parameters = new CompilerParameters();
            parameters.GenerateExecutable = false;
            parameters.GenerateInMemory = true;
            //parameters.OutputAssembly = "DynamicCode.dll"; // if specified creates the DLL
            CompilerResults results = icc.CompileAssemblyFromSource(parameters, code);

然后我可以用反射调用方法:

                Console.WriteLine("Input two strings, and I will concate them with reflection:");
                var s1 = Console.ReadLine();
                var s2 = Console.ReadLine();
                var result = (string)results.CompiledAssembly.GetType("CodeInjection.DynConcatenateString").GetMethod("Concatenate").Invoke(null, new object[] { s1, s2 });

                Console.WriteLine();
                Console.WriteLine("Result:");
                Console.WriteLine(result);

但我想调用这样的东西:

                Console.WriteLine("Input two strings, and I will concate them with dynamic type:");
                var s1 = Console.ReadLine();
                var s2 = Console.ReadLine();

                dynamic type = results.CompiledAssembly.GetType("CodeInjection.DynConcatenateString");
                var resultA = (string)type.Concatenate(s1, s2); // runtime error
                // OR
                var resultB = (string)CodeInjection.DynConcatenateString.Concatenate(s1, s2); // compile error (cannot find assembly)


                Console.WriteLine();
                Console.WriteLine("Result:");
                Console.WriteLine(resultA);
                Console.WriteLine(resultB);

结果B会更好。任何想法如何去做？我需要严格的 .NET 4.0，我们还没有更新到 4.5(因为团队的一半使用 VS 2010)。 (我可以用反射调用，我知道，我只是在寻找另一种方法，因为我们需要测试动态代码)

Answer 1

您不能在这种情况下直接使用dynamic。 dynamic 总是需要一个类实例，但您试图调用静态类中的方法，因此您没有类实例。

但是，您可以创建一个辅助类并将其与 dynamic 结合使用:

public class StaticMethodInvoker : DynamicObject
{
    Type _containingType;

    public StaticMethodInvoker(Type containingType)
    {
        _containingType = containingType;
    }

    public override bool TryInvokeMember(
        InvokeMemberBinder binder, Object[] args, out Object result)
    {
        result = _containingType.InvokeMember
            binder.Name,
            BindingFlags.Static | BindingFlags.InvokeMethod | BindingFlags.Public,
            null, null, args);
        return true;
    }
}

用法:

var type = results.CompiledAssembly.GetType("CodeInjection.DynConcatenateString");
dynamic DynConcatenateString = new StaticMethodInvoker(type);
string result = DynConcatenateString.Concatenate(s1, s2);