C# |类型。IsAssignableFrom(类型)方法

原文:https://www . geesforgeks . org/c-sharp-type-isassignablefromtype-method/

类型。IsAssignableFrom(类型)方法用于确定指定类型的实例是否可以分配给当前类型的变量。

语法:公共虚拟 bool IsAssignableFrom(Type c)； 这里是拿类型和现在的类型比较。

返回值:如果下列任一条件为真，则该方法返回真:

  • c 和当前实例表示相同的类型。
  • c 直接或间接从当前实例派生。如果 c 从当前实例继承，则直接从当前实例派生；如果 c 从继承自当前实例的一个或多个类的继承中继承，则它从当前实例间接派生。
  • 当前实例是 c 实现的接口。
  • c 是泛型类型参数，当前实例表示 c 的一个约束。

以下程序说明了类型的使用。IsAssignableFrom() 方法:

例 1:

// C# program to demonstrate the
// Type.IsAssignableFrom() Method
using System;
using System.Globalization;
using System.Reflection;
using System.IO;

// Defining MyClass extended
// from TypeDelegator
public class MyClass : TypeDelegator { }

class GFG {

    // Main Method
    public static void Main()
    {
        // Declaring and initializing object of Type
        Type objType = typeof(TypeDelegator);

        // Getting array of Properties by
        // using GetProperties() Method
        bool status = objType.IsAssignableFrom(typeof(MyClass));

        // Display the Result
        if (status)
            Console.WriteLine("Instance of a specified type can be "
                   + "assigned to a variable of the current type.");
        else
            Console.WriteLine("Instance of a specified type can't be "
                     + "assigned to a variable of the current type.");
    }
}

Output:

Instance of a specified type can be assigned to a variable of the current type.

例 2:

// C# program to demonstrate the
// Type.IsAssignableFrom() Method
using System;
using System.Globalization;
using System.Reflection;
using System.IO;

class GFG {

    // Main Method
    public static void Main()
    {
        // Declaring and initializing object of Type
        Type objType = typeof(double);

        // Getting array of Properties by
        // using GetProperties() Method
        bool status = objType.IsAssignableFrom(typeof(int));

        // Display the Result
        if (status)
            Console.WriteLine("Instance of a specified type can be "
                   + "assigned to a variable of the current type.");
        else
            Console.WriteLine("Instance of a specified type can't be "
                     + "assigned to a variable of the current type.");
    }
}

Output:

Instance of a specified type can't be assigned to a variable of the current type.

参考:

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