如何在C＃中的属性或const上访问Description属性？

如何访问const或属性上的Description属性，即

public static class Group { [Description( "Specified parent-child relationship already exists." )] public const int ParentChildRelationshipExists = 1; [Description( "User is already a member of the group." )] public const int UserExistsInGroup = 2; } 

要么

 public static class Group { [Description( "Specified parent-child relationship already exists." )] public static int ParentChildRelationshipExists { get { return 1; } } [Description( "User is already a member of the group." )] public static int UserExistsInGroup { get { return 2; } } } 

在调用类中，我想访问Description属性，即

 int x = Group.UserExistsInGroup; string description = Group.UserExistsInGroup.GetDescription(); // or similar 

我也对其他方法的想法持开放态度。

编辑：我应该提到我已经看到这里提供的示例： 自动实现的属性是否支持属性？

但是，我正在寻找一种方法来访问description属性，而不必在属性类型中输入字符串文字，即，我宁愿不这样做：

 typeof(Group).GetProperty("UserExistsInGroup"); 

类似于扩展方法的东西; 类似于以下方法，它将通过扩展方法返回Enum上的Description属性：

 public static String GetEnumDescription( this Enum obj ) { try { System.Reflection.FieldInfo fieldInfo = obj.GetType().GetField( obj.ToString() ); object[] attribArray = fieldInfo.GetCustomAttributes( false ); if (attribArray.Length > 0) { var attrib = attribArray[0] as DescriptionAttribute; if( attrib != null ) return attrib.Description; } return obj.ToString(); } catch( NullReferenceException ex ) { return "Unknown"; } } 

Answer 1

您可以调用MemberInfo.GetCustomAttributes（）来获取在Type成员上定义的任何自定义属性。 您可以通过执行以下操作获取属性的MemberInfo ：

 PropertyInfo prop = typeof(Group).GetProperty("UserExistsInGroup", BindingFlags.Public | BindingFlags.Static); 

Answer 2

请尝试以下方法

 var property = typeof(Group).GetProperty("UserExistsInGroup"); var attribute = property.GetCustomAttributes(typeof(DescriptionAttribute), true)[0]; var description = (DescriptionAttribute)attribute; var text = description.Description; 

Answer 3

好的，我已经看过你的编辑，我不确定你能用扩展方法做到这一点，因为他们会意识到包含类的类型。

这听起来有点古怪，但是如何创建一个新的类“DescribedInt”，它会有一个隐式的强制转换操作符让你自动将它用作int？ 你几乎可以使用你描述的方式。 你仍然会有一个描述，但是当你需要像Int一样使用它时，你不需要获得.Data属性……

例如：

 private void ExampleUse() { int myvalue = Group.A; //see, no need to cast or say ".Data" - implicit cast string text = Group.A.Description; 

//做有价值的东西……}

 public static class Group { public static DescribedInt A = new DescribedInt(12, "some description"); public static DescribedInt B = new DescribedInt(88, "another description"); } public class DescribedInt { public readonly int data; public readonly string Description; public DescribedInt(int data, string description) { this.data = data; this.Description = description; } //automatic cast to int public static implicit operator int(DescribedInt orig) { return orig.data; } //public DescribedInt(string description) //{ // this.description = description; //} //if you ever need to go the "other way" //public static implicit operator DescribedInt(int orig) //{ // return new DescribedInt(orig, ""); //} } 

Answer 4

这是我用于处理.NET中的自定义属性的辅助类

 public class AttributeList : List { /// 
 /// Gets a list of custom attributes /// 
 ///  ///  public static AttributeList GetCustomAttributeList(ICustomAttributeProvider propertyInfo) { var result = new AttributeList(); result.AddRange(propertyInfo.GetCustomAttributes(false).Cast()); return result; } /// 
 /// Finds attribute in collection by its type /// 
 ///  ///  public T FindAttribute() where T : Attribute { return (T)Find(x => typeof(T).IsAssignableFrom(x.GetType())); } public bool IsAttributeSet() where T : Attribute { return FindAttribute() != null; } } 

还为MsTest进行了unit testing，展示了如何使用这个类

 [TestClass] public class AttributeListTest { private class TestAttrAttribute : Attribute { } [TestAttr] private class TestClass { } [TestMethod] public void Test() { var attributeList = AttributeList.GetCustomAttributeList(typeof (TestClass)); Assert.IsTrue(attributeList.IsAttributeSet()); Assert.IsFalse(attributeList.IsAttributeSet()); Assert.IsInstanceOfType(attributeList.FindAttribute(), typeof(TestAttrAttribute)); } } 

http://www.kozlenko.info/2010/02/02/getting-a-list-of-custom-attributes-in-net/