簡單反射練習

主要是：

• 利用反射對實例進行構造；
• 以及調用實例的方法；

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Security;
using System.Security.Permissions;
using System.Security.Policy;
using System.Text;
using System.Threading.Tasks;

namespace AssemblyBuilder
{
    class Program
    {
        public static Assembly ReadAssembly(string assemblyPath)
        {
            return Assembly.LoadFrom(assemblyPath);
        }

        public static Assembly ReadAssembly(Stream stream)
        {
            SecurityPermission securityPermission = new SecurityPermission(SecurityPermissionFlag.ControlEvidence);
            securityPermission.Assert();
            int num = (int)stream.Length;
            byte[] array = new byte[num];
            stream.Read(array, 0, num);
            try
            {
                return Assembly.Load(array);
            }
            finally
            {
                CodeAccessPermission.RevertAssert();
            }
        }

        public static Stream ReadAssemblyToStream(string assemblyPath)
        {
            FileStream fileStream = new FileStream(assemblyPath, FileMode.Open, FileAccess.Read, FileShare.Read);
            try
            {
                int num = (int)fileStream.Length;
                byte[] array = new byte[num];
                fileStream.Read(array, 0, num);
                return new MemoryStream(array);
            }
            finally
            {
                fileStream.Close();
            }
        }

        static void Main(string[] args)
        {
            Stream assemblyStream = ReadAssemblyToStream("./Lambda_Test.exe");
            var assembly = ReadAssembly(assemblyStream);

            //使用 InvokeMember 調用構造函數初始化實例也能夠
            var programInstance = assembly.CreateInstance("FactoryMode.Program");   
            if (programInstance == null)
            {
                Console.WriteLine("There is no this type");
            }
            else
            {
                var myType = programInstance.GetType();
                Console.WriteLine("Type name is {0}", myType.ToString());

                MethodInfo[] methods = myType.GetMethods(BindingFlags.Instance | BindingFlags.Public | BindingFlags.Static);
                Console.WriteLine("Method number:{0}", methods.Length);
                foreach(var method in methods)
                {
                    //怎樣經過反射調用方法？
                    if(method.Name == "NotMainMethod")
                    {
                        Console.WriteLine("Find method, name:{0}", method.Name);

                        //沒有實例直接用類型進行 InvokeMember 調用，須要調用類型的構造函數後再調用目標方法（前提示有定義構造函數），要帶上 BindingFlags.CreateInstance                  
                        //myType.InvokeMember("NotMainMethod", BindingFlags.Public | BindingFlags.CreateInstance, null, null, null);

                        //使用已有實例時，就要指定 BindingFlags.Instance
                        myType.InvokeMember("NotMainMethod", BindingFlags.Public | BindingFlags.Instance | BindingFlags.InvokeMethod, null, programInstance, null);

                        //有實例則直接使用
                        method.Invoke(programInstance, null);
                    }
                }
            }

            Console.ReadKey();
        }
    }
}

 

12.2 補充構造實例：

public class TestObject
    {
        public string TestString1 { get; set; }

        public string TestString2 { get; set; }

        public TestObject()
        {

        }

        public TestObject(string testString1, string testString2)
        {
            TestString1 = testString1;
            TestString2 = testString2;
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            var tagType = typeof(TestObject);
            string[] paramArray = new string[] { "Hello", "World" };
            Type[] typeArray = paramArray.Select(obj => obj.GetType()).ToArray();
            ConstructorInfo constructor = tagType.GetConstructor(typeArray);
            var tagObject = (TestObject)constructor.Invoke(paramArray);
            Console.ReadLine();
        }
    }