Id字段上的DbKey就是自定義特性

/// <summary> /// 用戶信息 /// </summary> public class User {[DbKey]public string Id { get; set; }public string Name { get; set; } }

繼承Attribute，實現自定義特性DbKey

namespace CustomerAttribute {/// <summary>/// 數據庫主鍵/// </summary>public class DbKey : Attribute{public string Description { get; set; }public DbKey(){}public DbKey(string description){this.Description = description;}} } namespace CustomerAttribute {/// <summary>/// 用戶信息/// </summary>public class User{[DbKey]public string Id { get; set; }public string Name { get; set; }}/// <summary>/// 用戶角色/// </summary>public class UserRole{[DbKey("用戶ID")]public string UserId { get; set; }[DbKey("角色ID")]public string RoleId { get; set; }} } namespace CustomerAttribute {class Program{/// <summary>/// 獲取數據庫主鍵字段/// </summary>/// <typeparam name="T"></typeparam>/// <returns></returns>private static IEnumerable<PropertyInfo> getDbKeyFields<T>(){// 獲取當前類中的公共字段var fields = typeof(T).GetProperties();// 查找有DbKey特性的字段var keyFields = fields.Where(field => (DbKey)Attribute.GetCustomAttribute(field, typeof(DbKey)) != null);return keyFields;}private static string getDescription(PropertyInfo field){string result = string.Empty;var dbKey = (DbKey)Attribute.GetCustomAttribute(field, typeof(DbKey));if (dbKey != null) result = dbKey.Description;return result;}static void Main(string[] args){try{var userKeyFields = getDbKeyFields<User>();Console.WriteLine("User表的主鍵為:" + string.Join(",", userKeyFields.Select(field => field.Name)));var userRoleKeyFields = getDbKeyFields<UserRole>();Console.WriteLine("UserRole表的主鍵為:" + string.Join(",", userRoleKeyFields.Select(field => field.Name)));foreach (PropertyInfo field in userRoleKeyFields){string description = getDescription(field);Console.WriteLine(string.Format("{0}字段的描述信息為:{1}", field.Name, description));}}catch (Exception ex){Console.WriteLine(ex);}finally{Console.ReadLine();}}} } View Code

一些Orm的實現，就是通過解析特性信息，動態生成數據庫表

轉載于:https://www.cnblogs.com/jh007/p/6124179.html

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