综合应用WPF/WCF/WF/LINQ之十二：LINQ的ORM功能中对自定义的Entity Class的支持

最新推荐文章于 2023-12-28 19:21:56 发布

转载最新推荐文章于 2023-12-28 19:21:56 发布 · 108 阅读

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原文链接：https://yq.aliyun.com/articles/409208

文章标签：

#数据库 #runtime

本文介绍如何使用SqlMetal.exe工具从DBML文件生成Mapping程序，并手动调整存储过程GetEmployeeByEmployeeId的返回类型，使其匹配自定义的EmployeeInfo类。

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首先，我们使用SqlMetal.exe程序从DBML文件生成Mapping程序：

1 SqlMetal.exe /code:"..\Eallies.OA.DAL.DBML\Database.cs" "..\Eallies.OA.DAL.DBML\Database.dbml"

　　我们查看生成的Database.cs文件，发现关于存储过程GetEmployeeByEmployeeId的代码如下：

1 [Function(Name="dbo.GetEmployeeByEmployeeId")]

2 public ISingleResult<GetEmployeeByEmployeeIdResult> GetEmployeeByEmployeeId([Parameter(Name="EmployeeId", DbType="Int")] System.Nullable<int> employeeId)

3 {

4 IExecuteResult result = this.ExecuteMethodCall(this, ((MethodInfo)(MethodInfo.GetCurrentMethod())), employeeId);

5 return ((ISingleResult<GetEmployeeByEmployeeIdResult>)(result.ReturnValue));

6 }

　　显然，LINQ认为该存储过程返回的结果的Entity Class为GetEmployeeByEmployeeIdResult，但这却不是我们所期望的，实际上我们已经定义了Info类用于保存返回的结果：

1 using System;

2 using System.Collections;

3 using System.Collections.Generic;

4 using System.Linq;

5 using System.Text;

6 using System.Runtime.Serialization;

7 using System.Data.Linq;

8 using System.Data.Linq.Mapping;

9 using Eallies.OA.Info.Enum;

11 namespace Eallies.OA.Info

12 {

13 [DataContract]

14 [Serializable]

15 public class EmployeeInfo

16 {

17 private Int32 _EmployeeId;

18 private String _EmployeeNo;

19 private String _EmployeeName;

20 private Int32 _DepartmentId;

21 private Int32 _PositionId;

22 private Nullable<Int32> _EmployeeManager;

23 private Boolean _EmployeeGender;

24 private DateTime _EmployeeEntryDate;

25 private Nullable<DateTime> _EmoplyeeBirthday;

26 private String _EmployeePhone;

27 private String _EmployeeEmail;

28 private EmployeeStatusEnum _EmployeeStatus;

30 [DataMember]

31 [Column(Storage = "_EmployeeId", DbType = "Int NOT NULL", CanBeNull = false)]

32 public Int32 EmployeeId

33 {

34 get { return this._EmployeeId; }

35 set { this._EmployeeId = value; }

36 }

38 [DataMember]

39 [Column(Storage = "_EmployeeNo", DbType = "NVarChar(50) NOT NULL", CanBeNull = false)]

40 public String EmployeeNo

41 {

42 get { return this._EmployeeNo; }

43 set { this._EmployeeNo = value; }

44 }

46 [DataMember]

47 [Column(Storage = "_EmployeeName", DbType = "NVarChar(50) NOT NULL", CanBeNull = false)]

48 public String EmployeeName

49 {

50 get { return this._EmployeeName; }

51 set { this._EmployeeName = value; }

52 }

54 [DataMember]

55 [Column(Storage = "_DepartmentId", DbType = "Int NOT NULL", CanBeNull = false)]

56 public Int32 DepartmentId

57 {

58 get { return this._DepartmentId; }

59 set { this._DepartmentId = value; }

60 }

62 [DataMember]

63 [Column(Storage = "_PositionId", DbType = "Int NOT NULL", CanBeNull = false)]

64 public Int32 PositionId

65 {

66 get { return this._PositionId; }

67 set { this._PositionId = value; }

68 }

70 [DataMember]

71 [Column(Storage = "_EmployeeManager", DbType = "Int", CanBeNull = true)]

72 public Nullable<Int32> EmployeeManager

73 {

74 get { return this._EmployeeManager; }

75 set { this._EmployeeManager = value; }

76 }

78 [DataMember]

79 [Column(Storage = "_EmployeeGender", DbType = "Bit NOT NULL", CanBeNull = false)]

80 public Boolean EmployeeGender

81 {

82 get { return this._EmployeeGender; }

83 set { this._EmployeeGender = value; }

84 }

86 [DataMember]

87 [Column(Storage = "_EmployeeEntryDate", DbType = "DateTime NOT NULL", CanBeNull = false)]

88 public DateTime EmployeeEntryDate

89 {

90 get { return this._EmployeeEntryDate; }

91 set { this._EmployeeEntryDate = value; }

92 }

94 [DataMember]

95 [Column(Storage = "_EmoplyeeBirthday", DbType = "DateTime", CanBeNull = true)]

96 public Nullable<DateTime> EmoplyeeBirthday

97 {

98 get { return this._EmoplyeeBirthday; }

99 set { this._EmoplyeeBirthday = value; }

100 }

101

102 [DataMember]

103 [Column(Storage = "_EmployeePhone", DbType = "NVarChar(50)", CanBeNull = true)]

104 public String EmployeePhone

105 {

106 get { return this._EmployeePhone; }

107 set { this._EmployeePhone = value; }

108 }

109

110 [DataMember]

111 [Column(Storage = "_EmployeeEmail", DbType = "NVarChar(50)", CanBeNull = true)]

112 public String EmployeeEmail

113 {

114 get { return this._EmployeeEmail; }

115 set { this._EmployeeEmail = value; }

116 }

117

118 [DataMember]

119 [Column(Storage = "_EmployeeStatus", DbType = "Int NOT NULL", CanBeNull = false)]

120 public EmployeeStatusEnum EmployeeStatus

121 {

122 get { return this._EmployeeStatus; }

123 set { this._EmployeeStatus = value; }

124 }

125 }

126 }

　　这时，我们也可以手动或者采用程序将GetEmployeeByEmployeeIdResult改成EmployeeInfo，幸运的是，LINQ也能正确的识别我们的这种更改。然后，我们就可以将LINQ自动生成的GetEmployeeByEmployeeIdResult类彻底删除了。
　　值得注意的是：由于Info类是应用于整个系统各个环节的，所以它有一些特别的定义。
　　我们注意到这个类加了DataContract之类的标志，这是用于WCF技术的；它还加了Serializable标志，这是用于WF技术的，在将Workflow实例持久化到数据库中时，要求这个类可序列化；另外，它还加了Column标志，这是用于LINQ技术的。

本文转自 Eallies 51CTO博客，原文链接：http://blog.51cto.com/eallies/79031，如需转载请自行联系原作者