Question

是否可以从属性本身内部获取属性的值？例如：

public class TestModel
{
    [TestAttribute(Value="TestValue")]
    public TestClass TestProperty { get; set; }

    [TestAttribute(Value="AnotherValue")]
    public TestClass AnotherTestProperty { get; set; }
}

public class TestClass
{
    public string ReturnSomething()
    {
        // Get 'TestValue' or 'AnotherValue'
        // from 'TestAttribute' here depending on
        // which property ReturnSomething() is called on
    }
}

修改：澄清一下。我试图实现这一点，而不传递对父项的任何引用，或任何表示属性名称的字符串到ReturnSomething方法。

Answer 1

这对我有用：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace DemoApp
{
    class Program
    {
        static void Main(string[] args)
        {
            TestClass testClass = new TestClass();
            Console.WriteLine("Return-Value: " + testClass.ReturnSomething("TestProperty", typeof(TestModel)));
            Console.WriteLine("Return-Value: " + testClass.ReturnSomething("AnotherTestProperty", typeof(TestModel)));

            Console.ReadLine();
        }
    }

    public class TestAttribute : Attribute
    {
        public string Value
        {
            get;
            set;
        }
    }

    public class TestModel
    {
        [TestAttribute(Value = "TestValue")]
        public TestClass TestProperty { get; set; }

        [TestAttribute(Value = "AnotherValue")]
        public TestClass AnotherTestProperty { get; set; }
    }

    public class TestClass
    {
        public string ReturnSomething(string propertyName, Type modelType)
        {
            string returnValue = "";

            foreach (var property in modelType.GetProperties())
            {
                if (property.Name == propertyName)
                {
                    // Find Attributes
                    Attribute[] cAttributes = property.GetCustomAttributes(true).OfType<Attribute>().ToArray();

                    if (cAttributes != null)
                    {
                        // Iterate throught all attributes
                        foreach (System.Attribute cAttribute in cAttributes)
                        {
                            if (cAttribute is TestAttribute)
                            {
                                returnValue = (cAttribute as TestAttribute).Value;
                                break; // Break after first
                            }
                        }
                    }
                }
            }

            return returnValue;
        }
    }
}

Answer 2

是的，可以使用.net反射获取属性本身内属性的属性。要做到这一点，你必须充实属性的getter代码，而不是使用自动属性。

[AttributeUsage(AttributeTargets.Property, AllowMultiple = false)]
    class TestAttribute : Attribute
    {
        public string Value { get; set; }
    }

    [Test(Value = "Hello")]
    public string MyTestProperty
    {
        get
        {
            var typeInfo = GetType();
            // Get the PropertyInfo descriptor for this property
            var propInfo = typeInfo.GetProperty("MyTestProperty");

            // Get custom attributes applied to the property
            var attr = propInfo.GetCustomAttributes(false).OfType<TestAttribute>().FirstOrDefault();

            // If we have an attribute, then return its Value
            return attr != null ? attr.Value : "No Attribute";
        }
    }

获取在父级中应用于此属性的属性

2 个答案: