该类型的作用是绕过编译时类型检查， 改为在运行时解析这些操作。 dynamic 类型简化了对 COM API（例如 Office Automation API）、动态 API（例如 IronPython 库）和 HTML 文档对象模型 (DOM) 的访问（参考msdn）

 dynamic dyn = 1;object obj = 1;dyn = dyn + 3;//不报错，因为dynamic类型只有在程序运行时才会执行类型检查obj = obj + 3;//报错，因为编译时进行了类型检查，发现不合适

 class ExampleClass{static dynamic field;dynamic prop { get; set; }public dynamic exampleMethod(dynamic d){dynamic local = "Local variable";int two = 2;if (d is int){return local;}else{return two;}}}

调用

   ExampleClass ec = new ExampleClass();Console.WriteLine(ec.exampleMethod(10));Console.WriteLine(ec.exampleMethod("value"));// The following line causes a compiler error because exampleMethod// takes only one argument.Console.WriteLine(ec.exampleMethod(10, 4));//报错ExampleClass类型对象在编译时执行类型检查dynamic dynamic_ec = new ExampleClass();Console.WriteLine(dynamic_ec.exampleMethod(10));// Because dynamic_ec is dynamic, the following call to exampleMethod// with two arguments does not produce an error at compile time.// However, itdoes cause a run-time error. Console.WriteLine(dynamic_ec.exampleMethod(10, 4));//不报错ExampleClass类型对象在编译时执行类型检查，但是程序运行起来后也会报错。

注意：动态类型由于在运行时才执行编译，所以效率会比静态编译的低，要慎用