MVC-CodeFirst（一）

MVC-CodeFirst（一）

　　最近刚做完一个Web的项目，不过也是第一次接触MVC，做完以后对MVC朦朦胧胧，所以在此就查了好多资料，看了好多大牛的博客，也不知道最近为什么这么多MVC系列，不过刚好有助于我的学习，顺便自己也记录一些学到的东西，不过还是有很多不懂的地方，如果有大牛路过，请指点一二。

CodeFirst

　　建了三个项目，分别是DAL（DB层），ModelEntities（实体层），MyWeb.EntitiesConfiguration（实体配置层）。

ModelEntities

　　简单的建立了几个表，主要是想分别体现一对多，多对多的特征和写法。

User实体

 1     [Table("t_User")]

 2     public class User

 3     {

 4         [Key]

 5         [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]

 6         public int Id { get; set; }

 7 

 8         public string Name { get; set; }

 9 

10         public string UserName { get; set; }

11 

12         public string Password { get; set; }

13 

14         public virtual ICollection<Employee> CreatorList { get; set; }

15 

16         public virtual ICollection<Employee> ModifiedPersonList { get; set; }

17     }

View Code

Employee实体

 1     [Table("t_Employee")]

 2     public class Employee

 3     {

 4         public Employee()

 5         {

 6             this.WorkRecordList = new HashSet<WorkRecord>();

 7             this.ContractList = new HashSet<Contract>();

 8             this.EnrollmentList = new HashSet<Enrollment>();

 9         }

10 

11 

12         [Key]

13         [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]

14         public int Id { get; set; }

15 

16         [StringLength(20,ErrorMessage="员工姓名最大长度为50！")]

17         [Display(Name="员工姓名")]

18         public string EmployeeName { get; set; }

19 

20         [StringLength(20,ErrorMessage="联系方式最长为20！")]

21         [Display(Name= "员工联系方式")]

22         public string EmployeePhone { get; set; }

23 

24 

25         [ForeignKey("Creator")]

26         public int CreatorId { get; set; }

27 

28         //ON DELETE NO ACTION 或 ON UPDATE NO ACTION

29         [ForeignKey("ModifiedPerson")]

30         public int ModifiedPersonId { get; set; }

31 

32         public virtual User Creator { get; set; }

33 

34 

35         public virtual User ModifiedPerson { get; set; }

36 

37         public virtual ICollection<Enrollment> EnrollmentList { get; set; }

38 

39         public virtual ICollection<Contract> ContractList { get; set; }

40 

41         public virtual ICollection<WorkRecord> WorkRecordList { get; set; }

42     }

View Code

Job实体

 1     [Table("t_Job")]

 2     public class Job

 3     {

 4         [Key]

 5         [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]

 6         public int Id { get; set; }

 7 

 8         [Display(Name = "职位名称")]

 9         public string JobName { get; set; }

10 

11         public virtual ICollection<Enrollment> EnrollmentList { get; set; }

12     }

View Code

Enroollment实体

 1     [Table("t_Enrollment")]

 2     /// <summary>

 3     /// 关系（员工和职位，多对多的关系）

 4     /// </summary>

 5     public class Enrollment

 6     {

 7         [Key]

 8         [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]

 9         public int Id { get; set; }

10 

11         /// <summary>

12         /// 职工Id

13         /// </summary>

14         [ForeignKey("Employee")]

15         [Display(Name="员工Id")]

16         public int EmployeeId { get; set; }

17 

18         [ForeignKey("Job")]

19         public int JobId { get; set; }

20 

21 

22         public virtual Employee Employee { get; set; }

23 

24         public virtual Job Job { get; set; }

25     }

View Code

WorkRecord实体

 1  /// <summary>

 2     /// 一对多（Employee）

 3     /// </summary>

 4     [Table("t_WorkRecord")]

 5     public class WorkRecord

 6     {

 7         [Key]

 8         [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]

 9         public int Id { get; set; }

10 

11         [ForeignKey("Employee")]

12         public int EmployeeId { get; set; }

13 

14         public DateTime CreatedDate { get; set; }

15 

16         /// <summary>

17         /// 不能包含“@”，并不能为空

18         /// </summary>

19         [ValidationAttributeHelper]

20         public string WorkContent { get; set; }

21 

22         public virtual Employee Employee { get; set; }

23     }

View Code

Contract实体

 1 /// <summary>

 2     ///  合同表(一对多Employee)

 3     /// </summary>

 4     [Table("t_Contract")]

 5     public class Contract

 6     {

 7         [Key]

 8         [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]

 9         public int Id { get; set; }

10 

11         public string ContractName { get; set; }

12 

13         [ForeignKey("Employee")]

14         public int EmployeeId { get; set; }

15 

16         public virtual Employee Employee { get; set; }

17     }

View Code

各个配置的含义

[Table("t_User")]该表在数据库中的名称为“t_User”；

[Key]该字段为主键；

[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]该字段为自增；

[ForeignKey("Employee")]该字段为外键，对应虚的属性public virtual Employee Employee { get; set; }，也就是该字段是Employee的外键；

[Display(Name="员工姓名")]该字段显示的内容；

[StringLength(20,ErrorMessage="员工姓名最大长度为20！")]该字段的长度，如果超出，提示相应的错误；

1  [ForeignKey("Creator")]

2 public int CreatorId { get; set; }

3 public virtual User Creator { get; set; }

属性Creator是外键User，可以没有CreatorId这个字段，数据库会自动创建一个名为“Creator_Id”的字段，设为外键，与User管理，不过不建议这样做，一方面命名不是自己的，另一方面使用不方便；

1 public virtual ICollection<Employee> CreatorList { get; set; }

Employee表与User关联的同时，也需要在User表里建立User一对多属性，否则会建立失败；

[ValidationAttributeHelper]该字段需符合该规则，这个规则是自己定义的，也是在看一位大牛的文章的时候看到的，就自己也写了一个，具体代码：

 1  /// <summary>

 2     /// 创建已定义验证

 3     /// </summary>

 4     public class ValidationAttributeHelper : ValidationAttribute

 5     {

 6         protected override ValidationResult IsValid(object value, ValidationContext validationContext)

 7         {

 8             //检查是否为空值

 9             if (value == null)

10             {

11                 return new ValidationResult("不能为空！");

12             }

13             else

14             {

15                 if (value.ToString().Contains("@"))

16                 {

17                     return new ValidationResult("不能包含@符号");

18                 }

19             }

20             return ValidationResult.Success;

21         }

22     }

View Code

　　先到这吧~