C＃类可以从其接口继承属性吗？

Question

这似乎暗示“否”。不幸的是。

[AttributeUsage(AttributeTargets.Interface | AttributeTargets.Class,

 AllowMultiple = true, Inherited = true)]

public class CustomDescriptionAttribute : Attribute

{

    public string Description { get; private set; }

    public CustomDescriptionAttribute(string description)

    {

        Description = description;

    }

}

[CustomDescription("IProjectController")]

public interface IProjectController

{

    void Create(string projectName);

}

internal class ProjectController : IProjectController

{

    public void Create(string projectName)

    {

    }

}

[TestFixture]

public class CustomDescriptionAttributeTests

{

    [Test]

    public void ProjectController_ShouldHaveCustomDescriptionAttribute()

    {

        Type type = typeof(ProjectController);

        object[] attributes = type.GetCustomAttributes(

            typeof(CustomDescriptionAttribute),

            true);

        // NUnit.Framework.AssertionException:   Expected: 1   But was:  0

        Assert.AreEqual(1, attributes.Length);

    }

}

类可以从接口继承属性吗？还是我在这里树错树了？

Answer 1

否。每当实现接口或重写派生类中的成员时，都需要重新声明属性。如果您只关心ComponentModel（而不是直接反射），则有一种方法（[AttributeProvider]）从现有类型中建议属性（以避免重复），但这仅对属性和索引器用法有效。举个例子：using System;using System.ComponentModel;class Foo {    [AttributeProvider(typeof(IListSource))]    public object Bar { get; set; }    static void Main() {        var bar = TypeDescriptor.GetProperties(typeof(Foo))["Bar"];        foreach (Attribute attrib in bar.Attributes) {            Console.WriteLine(attrib);        }    }}输出：System.SerializableAttributeSystem.ComponentModel.AttributeProviderAttributeSystem.ComponentModel.EditorAttributeSystem.Runtime.InteropServices.ComVisibleAttributeSystem.Runtime.InteropServices.ClassInterfaceAttributeSystem.ComponentModel.TypeConverterAttributeSystem.ComponentModel.MergablePropertyAttribute