如何添加元数据

众所周知Entity Framwork自动生成的实体上没有注释。因为是数据库拖动过来生成的,所以也不能修改其代码.因为改后还会自动生成代码覆盖掉修改的.

 

那如何添加元数据呢.

手动添加元数据

引文地址:http://blog.csdn.net/blackant2/article/details/5461576

1. 添加一个新类。这个类的名字应与想要公开的实体类的名字一致。按照惯 例，在名字用包含.metadata。
2. 添加关键字partial来使类成为局部类。下面的代码示例了一个匹配名字为 Address实体类的局部类。

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   1. C# Copy Code  
   2. public partial class Address 
   3. { 
   4. }  
3. 在 局部类中，创建一个internal类作为元数据类。如下：

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   1. public partial class Address 
   2. { 
   3. internal sealed class AddressMetadata 
   4.   { 
   5.   } 
   6. } 
4. 对 局部类添加[MetadataTypeAttribute属性，并包含元数据类的类型。代码如下：

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   1. [MetadataTypeAttribute(typeof(Address.AddressMetadata))] 
   2. public partial class Address 
   3. { 
   4. internal sealed class AddressMetadata 
   5.   { 
   6.   } 
   7. }  
5. 在 元数据类中，添加和实体类中成员属性同名的成员属性。
6. 对成员属性添加属性批注。示例代码如下：

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   1. [MetadataTypeAttribute(typeof(Address.AddressMetadata))] 
   2. public partial class Address 
   3. { 
   4. internal sealed class AddressMetadata 
   5.     { 
   6. // Metadata classes are not meant to be instantiated.
   7. private AddressMetadata() 
   8.         { 
   9.         } 
   10. public int AddressID; 
   11.         [Required] 
   12.         [StringLength(60)] 
   13. public string AddressLine1; 
   14. public string AddressLine2; 
   15.         [Required] 
   16.         [StringLength(30)] 
   17. public string City; 
   18. public string CountryRegion; 
   19. public EntityCollection<customeraddress> CustomerAddresses; 
   20. public DateTime ModifiedDate; 
   21.         [Required] 
   22. public string PostalCode; 
   23.         [Exclude] 
   24. public Guid rowguid; 
   25. public string StateProvince; 
   26.     } 
   27. } 

又一个例子:

namespace ZYBW.ProjectMIS.Models.Dealer
{
    using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.ComponentModel.DataAnnotations;
    using System.Linq;
    using System.ServiceModel.DomainServices.Hosting;
    using System.ServiceModel.DomainServices.Server;

    // The MetadataTypeAttribute identifies TbDealerInfoManageMetadata as the class
    // that carries additional metadata for the TbDealerInfoManage class.
    [MetadataTypeAttribute(typeof(LawEnforcementType.LawEnforcementTypeMetadata))]
    public partial class LawEnforcementType
    {
        // This class allows you to attach custom attributes to properties
        // of the TbDealerInfoManage class.
        //
        // For example, the following marks the Xyz property as a
        // required property and specifies the format for valid values:
        //    [Required]
        //    [RegularExpression("[A-Z][A-Za-z0-9]*")]
        //    [StringLength(32)]
        //     [Display(Name = "")] public string Xyz { get; set; }
        internal sealed class LawEnforcementTypeMetadata
        {
            // Metadata classes are not meant to be instantiated.
            private LawEnforcementTypeMetadata()
            { }

            /// <summary>
            /// 农药ID
            /// </summary>
            [Display(Name = "ID")]
            public int ID
            {
                set;
                get;
            }
            /// <summary>
            /// 农药ID
            /// </summary>
            [Display(Name = "执法类别")]
            public string Name
            {
                set;
                get;
            }
            /// <summary>
            /// 农药ID
            /// </summary>
            [Display(Name = "值")]
            public string Value
            {
                set;
                get;
            }
        }
    }
}