c#中动态对象的RuntimeTypeHandle

向右看齐 2022-08-03 13:00 10阅读 0赞

它表示使用内部元数据标记的类型。

MSDN地址：[https://msdn.microsoft.com/zh-cn/library/system.runtimetypehandle.aspx][https_msdn.microsoft.com_zh-cn_library_system.runtimetypehandle.aspx]

PS：Type 是一个表示类型的抽象类；RuntimeType 是 Type 针对载入类型信息的具体实现；RuntimeTypeHandle 则是类型唯一的抽象句柄。参阅[http://www.cnblogs.com/dudu/articles/9984.html][http_www.cnblogs.com_dudu_articles_9984.html]【[Type, RuntimeType and RuntimeTypeHandle][http_www.cnblogs.com_dudu_articles_9984.html]】，此处摘录部分内容和代码：

RuntimeType 是 System 名字空间的内部类，用于实现对普通类型的运行时信息提供代码。Type中很多抽象函数如 Type.GetMethodImpl 都是在 RuntimeType 中实现的。与 TypeBuilder 等不同，RuntimeType 是类型的运行时表现。
        RuntimeTypeHandle 是运行时类型的抽象句柄，结构内部实际上是一个 Unamanged 指针。可以使用 Type.GetTypeFromHandle() 函数、Type.TypeHandle 属性和 Type.GetTypeHandle() 函数，完成在类型句柄、类型和对象之间的双向转换。例如：

MyClass1 cls = new MyClass1();
    
    Debug.Assert(cls.GetType().TypeHandle.Equals(Type.GetTypeHandle(cls)));
    Debug.Assert(Type.GetTypeFromHandle(cls.GetType().TypeHandle) == typeof(MyClass1));

using System;
    using System.Reflection;
    
    public class MyClass1
    {
        private int x=0;
        public int MyMethod()
        {
            return x;
        }
    }
    
    public class MyClass2
    {
        public static void Main()
        {
            MyClass1 myClass1 = new MyClass1();
    
            // Get the RuntimeTypeHandle from an object.
            RuntimeTypeHandle myRTHFromObject = Type.GetTypeHandle(myClass1);
            // Get the RuntimeTypeHandle from a type.
            RuntimeTypeHandle myRTHFromType = typeof(MyClass1).TypeHandle;
    
            Console.WriteLine("\nmyRTHFromObject.Value:  {0}", myRTHFromObject.Value);
            Console.WriteLine("myRTHFromObject.GetType():  {0}", myRTHFromObject.GetType());
            Console.WriteLine("Get the type back from the handle...");
            Console.WriteLine("Type.GetTypeFromHandle(myRTHFromObject):  {0}", 
                Type.GetTypeFromHandle(myRTHFromObject));
    
            Console.WriteLine("\nmyRTHFromObject.Equals(myRTHFromType):  {0}", 
                myRTHFromObject.Equals(myRTHFromType));
    
            Console.WriteLine("\nmyRTHFromType.Value:  {0}", myRTHFromType.Value);
            Console.WriteLine("myRTHFromType.GetType():  {0}", myRTHFromType.GetType());
            Console.WriteLine("Get the type back from the handle...");
            Console.WriteLine("Type.GetTypeFromHandle(myRTHFromType):  {0}", 
                Type.GetTypeFromHandle(myRTHFromType));
        }
    }
    
    /* This code example produces output similar to the following:
    
    myRTHFromObject.Value:  799464
    myRTHFromObject.GetType():  System.RuntimeTypeHandle
    Get the type back from the handle...
    Type.GetTypeFromHandle(myRTHFromObject):  MyClass1
    
    myRTHFromObject.Equals(myRTHFromType):  True
    
    myRTHFromType.Value:  799464
    myRTHFromType.GetType():  System.RuntimeTypeHandle
    Get the type back from the handle...
    Type.GetTypeFromHandle(myRTHFromType):  MyClass1
     */

[https_msdn.microsoft.com_zh-cn_library_system.runtimetypehandle.aspx]: https://msdn.microsoft.com/zh-cn/library/system.runtimetypehandle.aspx
[http_www.cnblogs.com_dudu_articles_9984.html]: http://www.cnblogs.com/dudu/articles/9984.html