記憶一下，以防遺忘

定義一個介面

 1 public interface IPropertyValidation
 2     {
 3         /// <summary>
 4         /// 驗證失敗後的錯誤資訊
 5         /// </summary>
 6         string ErrorInfo { get; set; }
 7 
 8         /// <summary>
 9         /// 是否通過驗證 預設為空
10         /// </summary>
11         bool? IsValidation { get
 
; set; }
12 
13         /// <summary>
14         /// 驗證單個屬性
15         /// </summary>
16         /// <param name="obj"></param>
17         /// <param name="propertyName"></param>
18         void Validate(object obj, string propertyName);
19 
20         ///// <summary>
21         ///// 驗證所有屬性
 
22         ///// </summary>
23         ///// <param name="obj"></param>
24         //void ValidatAll(object obj);
25     }

實現兩個特性類

 1 [AttributeUsage(AttributeTargets.Property, AllowMultiple = false)]
 2     public class StringLengthAttribute : Attribute, IPropertyValidation
 3     {
 4         private
 
 int _max;
 5         private int _min;
 6         public string ErrorInfo { get; set; }
 7         public bool? IsValidation { get; set; }
 8 
 9         public StringLengthAttribute(int min, int max)
10         {
11             this._min = min;
12             this._max = max;
13         }
14 
15         public void Validate(object obj, string propertyName)
16         {
17             var type = obj.GetType();
18             var property = type.GetProperty(propertyName);//獲取特定屬性;
19             if (property.IsDefined(typeof(IPropertyValidation), true))//如果屬性定義了這個特性
20             {
21                 var value = (string)property.GetValue(obj);//獲取屬性值
22                 if (value.Length < this._min || value.Length > this._max)
23                 {
24                     this.IsValidation = false;
25                 }
26                 else
27                 {
28                     this.IsValidation = true;
29                 }
30             }
31         }
32     }
33 
34 
35 
36 [AttributeUsage(AttributeTargets.Property, AllowMultiple = false)]
37     internal class PhoneNumberAttribute : Attribute, IPropertyValidation
38     {
39         public string ErrorInfo { get; set; }
40         public bool? IsValidation { get; set; }
41 
42         public void Validate(object obj, string propertyName)
43         {
44             var type = obj.GetType();
45             var property = type.GetProperty(propertyName);
46             if (property.IsDefined(typeof(IPropertyValidation), true))
47             {
48                 var value = (string)property.GetValue(obj);//獲取屬性值
49                 if (value.Length != 11)
50                 {
51                     this.IsValidation = false;
52                 }
53                 else
54                 {
55                     this.IsValidation = true;
56                 }
57             }
58         }
59     }

實現一個方法獲取驗證資訊

 1 public static void PropetyAtrributeValidation(object obj)
 2         {
 3             var type = obj.GetType();
 4             var properties = type.GetProperties();
 5             foreach (var property in properties)
 6             {
 7                 if (property.IsDefined(typeof(IPropertyValidation), true))
 8                 {
 9                     var attribute = (IPropertyValidation)property.GetCustomAttributes(typeof(IPropertyValidation), true)[0];
10                     attribute.Validate(obj, property.Name);//驗證屬性值
11                     if (attribute.IsValidation.HasValue && !attribute.IsValidation.Value)
12                     {
13                         Console.WriteLine($"{attribute.ErrorInfo}");
14                     }
15                 }
16             }
17         }

定義一個模型類

 1 public class Test
 2     {
 3         public int Age { get; set; }
 4 
 5         [StringLength(5, 10, ErrorInfo = "名稱長度需要大於5且小於10")]
 6         public string Name { get; set; }
 7 
 8         [StringLength(2, 4, ErrorInfo = "名稱長度需要大於2且小於4")]
 9         public string NickName { get; set; }
10 
11         [PhoneNumber(ErrorInfo = "電話號碼長度需要11位")]
12         public string PhoneNumber { get; set; }
13     }

執行

 1 private static void Main(string[] args)
 2         {
 3             var test = new Test()
 4             {
 5                 Name = "ABCDEFG",//符合規則
 6                 NickName = "A",//不符合規則
 7                 PhoneNumber = "185123456789",//不符合規則
 8             };
 9             PropetyAtrributeValidation(test);
10         }

結果