C# 对象实例几种方法

            //实例方法1

            //new
            CreateCalss cc1 = new CreateCalss();

            //实例方法2

            //获取当前程序集
            Assembly asse = Assembly.GetExecutingAssembly();

            //获取程序集对象Type t查看方法和字段
            Type t = asse.GetType("sp." + "CreateCalss");

            //创建对象类型
            CreateCalss cc2 = (CreateCalss)Activator.CreateInstance(t);

            //实例方法3

            //加载指定程序集并创建对象实例
            CreateCalss cc3 = (CreateCalss)Assembly.Load("sp").CreateInstance("sp.CreateCalss");

            //假设需求根据用户的选择创建一个实例 这个时候需要动态创建对象
            //比如选择A A a=new A();
            //比如选择B B b=new B();
            Assembly ass = Assembly.GetExecutingAssembly();
            Type tp = ass.GetType("sp."+"CreateCalss2");
            object o = Activator.CreateInstance(tp);
            Isp isp = o as Isp;
            isp.Open();

    public class CreateCalss : Isp
    {
        public int i;

        public void Open()
        {
            Console.WriteLine("");
        }
    }

    public class CreateCalss2 : Isp
    {
        public int i;

        public void Open()
        {
            Console.WriteLine("");
        }
    }

    interface Isp
    {
        void Open();
    }

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            Type type = typeof(ReflectTest);
            object reflectTest = Activator.CreateInstance(type);

            //不带参数且不返回值的方法的调用
            MethodInfo methodInfo = type.GetMethod("MethodWithNoParaNoReturn");
            methodInfo.Invoke(reflectTest, null);

            ReflectTest r = (ReflectTest)Activator.CreateInstance(type);
            r.MethodWithNoParaNoReturn();

            Console.WriteLine();

            ////不带参数且有返回值的方法的调用
            //methodInfo = type.GetMethod("MethodWithNoPara");
            //Console.WriteLine(methodInfo.Invoke(reflectTest, null).ToString());

            //Console.WriteLine();

            ////带参数且有返回值的方法的调用
            //methodInfo = type.GetMethod("Method1", new Type[] { typeof(string) });
            //Console.WriteLine(methodInfo.Invoke(reflectTest, new object[] { "测试" }).ToString());

            //Console.WriteLine();

            ////带多个参数且有返回值的方法的调用
            //methodInfo = type.GetMethod("Method2", new Type[] { typeof(string), typeof(int) });
            //Console.WriteLine(methodInfo.Invoke(reflectTest, new object[] { "测试", 100 }).ToString());

            ////Console.WriteLine();

            ////methodInfo = type.GetMethod("Method3", new Type[] { typeof(string), typeof(string) });
            ////string outStr = "";
            ////Console.WriteLine(methodInfo.Invoke(reflectTest, new object[] { "测试", outStr }).ToString());

            //Console.WriteLine();

            ////静态方法的调用
            //methodInfo = type.GetMethod("StaticMethod");
            //Console.WriteLine(methodInfo.Invoke(null, null).ToString());

            Console.ReadKey();
        }
    }

    public class ReflectTest
    {
        public void MethodWithNoParaNoReturn()
        {
            Console.WriteLine("不带参数且不返回值的方法");
        }

        public string MethodWithNoPara()
        {
            Console.WriteLine("不带参数且有返回值的方法");
            return "MethodWithNoPara";
        }

        public string Method1(string str)
        {
            Console.WriteLine("带参数且有返回值的方法");
            return str;
        }

        public string Method2(string str, int index)
        {
            Console.WriteLine("带参数且有返回值的方法");
            return str + index.ToString();
        }

        public string Method3(string str, out string outStr)
        {
            outStr = "bbbb";
            Console.WriteLine("带参数且有返回值的方法");
            return str;
        }

        public static string StaticMethod()
        {
            Console.WriteLine("静态方法");
            return "cccc";
        }
    }
}

反射：

class clsDemo
    {
        public void csDemo(string str)
        {
            MessageBox.Show(str);
        }
    }

 System.Type t = typeof(Person);
var obj = Activator.CreateInstance(t, null);
 t.InvokeMember("csDemo", System.Reflection.BindingFlags.InvokeMethod, null, obj, new object[] { "hell world!" });

使用 ：dynamic 

 dynamic obj= Activator.CreateInstance(t, null);
 obj.csDemo("hell world!");