433
技術社區[雲棲]
C# 自定義特性
1.代碼視圖：
2.RecordAttribute.cs
using System;
namespace 自定義特性
{
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = true, Inherited = false)]
public class RecordAttribute : Attribute
{
private readonly string _author; // 作者
private readonly DateTime _date; // 更新/創建 日期
private readonly string _recordType; // 記錄類型：更新/創建
// 構造函數，構造函數的參數在特性中也稱為“位置參數”。
//NOTE：注意構造函數的參數 date，必須為一個常量、Type類型、或者是常量數組，所以不能直接傳遞DateTime類型。
public RecordAttribute(string recordType, string author, string date)
{
_recordType = recordType;
_author = author;
_date = Convert.ToDateTime(date);
}
// 對於位置參數，通常隻提供get訪問器
public string RecordType
{
get { return _recordType; }
}
public string Author
{
get { return _author; }
}
public DateTime Date
{
get { return _date; }
}
// 構建一個屬性，在特性中也叫“命名參數”
public string Memo { get; set; }
}
}
3.Program.cs
using System;
using System.Reflection;
namespace 自定義特性
{
internal class Program
{
private static void Main(string[] args)
{
var demo = new DemoClass();
Console.WriteLine(demo.ToString());
MemberInfo reflection = typeof(DemoClass);
var recordAttributes =
Attribute.GetCustomAttributes(reflection, typeof(RecordAttribute)) as RecordAttribute[];
if (recordAttributes != null)
{
foreach (RecordAttribute attribute in recordAttributes)
{
if (attribute != null)
{
Console.WriteLine("時間：{0}", attribute.Date.ToString("yyyy-MM-dd HH:mm:ss"));
Console.WriteLine("作者：{0}", attribute.Author);
Console.WriteLine("備注：{0}", attribute.Memo);
}
}
}
Console.Read();
}
}
[Record("更新", "王五", "2012-12-24", Memo = "修改 ToString()方法")]
[Record("更新", "李四", "2012-12-18", Memo = "修改文件")]
[Record("創建", "張三", "2012-11-15", Memo = "創建文件")]
public class DemoClass
{
public override string ToString()
{
return "This is a demo class";
}
}
}
4.運行結果：
最後更新：2017-04-04 07:03:12