Question

我试图在EF6 Code First Migrations中通过MetadataType设置Precision。如果我直接在类中的属性上设置属性，它可以正常工作，但如果它在MetadataType类中则不行。

我能做些什么才能让它发挥作用（除了在课堂上直接装饰它们）？

我很乐意在C＃中接受答案......我会转换它。

用例：原始类不在我的代码/控件中。

测试控制台应用

Imports System.IO
Imports System.Data.Entity
Imports System.ComponentModel.DataAnnotations
Imports System.ComponentModel.DataAnnotations.Schema

Module Module1

    Friend MyAppSettings As New AppSettings
    Friend SqlConnect As String = String.Empty

    Sub Main()
        With New SqlClient.SqlConnectionStringBuilder() With {
            .DataSource = Path.Combine(MyAppSettings.SqlServer, MyAppSettings.SqlInstance),
            .InitialCatalog = MyAppSettings.SqlDatabase,
            .IntegratedSecurity = True, .PersistSecurityInfo = True,
            .MultipleActiveResultSets = True}

            SqlConnect = .ConnectionString
        End With

        With New MyEntities(SqlConnect)
            Try
                .Database.Initialize(True)
            Catch ex As Exception
                Debug.Print(ex.ToString)
            Finally
                .Dispose()
            End Try
        End With
    End Sub

End Module

<MetadataType(GetType(TestMetaData))>
Partial Public Class Test
    <Key>
    Public Property ID As Int64 = 0

    Public Property Description As String = String.Empty

    ' ** Precision works with Migrations when applied directly here **
    '<Precision(12, 6)>
    Public Property Measurement As Decimal?
End Class

Public Class TestMetaData
    <Column(TypeName:="varchar"), StringLength(100)>
    Public Property Description As String = String.Empty

    ' ** Precision FAILS with Migrations when applied through MetadataType **
    <Precision(15, 6)>
    Public Property Measurement As Decimal?
End Class

Public Class MyEntities
    Inherits DbContext

    Public Sub New()
        Database.SetInitializer(New MigrateDatabaseToLatestVersion(Of MyEntities, Migrations.Configuration)(True))
    End Sub

    Public Sub New(ConnectionString As String)
        MyBase.New(ConnectionString)
        Database.SetInitializer(New MigrateDatabaseToLatestVersion(Of MyEntities, Migrations.Configuration)(True))
    End Sub

    Protected Overrides Sub OnModelCreating(ModelBuilder As DbModelBuilder)
        Precision.ConfigureModelBuilder(ModelBuilder)
    End Sub

    Public Overridable Property TestData() As DbSet(Of Test)
End Class

<AttributeUsage(AttributeTargets.Property, AllowMultiple:=False)>
Public Class Precision
    Inherits Attribute

    Public Property Precision() As Byte
    Public Property Scale() As Byte

    Public Sub New(Precision As Byte, Scale As Byte)
        Me.Precision = Precision
        Me.Scale = Scale
    End Sub

    Public Shared Sub ConfigureModelBuilder(ByRef ModelBuilder As DbModelBuilder)
        With ModelBuilder.Properties.Where(Function(x) x.GetCustomAttributes(False).OfType(Of Precision).Any)
            .Configure(Function(c) c.HasPrecision(c.ClrPropertyInfo.GetCustomAttributes(False).OfType(Of Precision).First.Precision,
                                                  c.ClrPropertyInfo.GetCustomAttributes(False).OfType(Of Precision).First.Scale))
        End With
    End Sub

End Class

迁移代码

Imports System.Data.Entity.Migrations

Namespace Migrations

    Friend NotInheritable Class Configuration
        Inherits DbMigrationsConfiguration(Of MyEntities)

        Public Sub New()
            AutomaticMigrationsEnabled = False
            AutomaticMigrationDataLossAllowed = True
        End Sub
    End Class

    Partial Public Class BaseSchema
        Inherits DbMigration

        Public Overrides Sub Up()
            CreateTable(
                "dbo.Tests",
                Function(c) New With
                    {
                        .Clever_EDI_ID = c.Long(nullable:=False, identity:=True),
                        .Description = c.String(maxLength:=100, unicode:=False),
                        .Measurement = c.Decimal(precision:=18, scale:=2)
                    }) _
                .PrimaryKey(Function(t) t.Clever_EDI_ID)
        End Sub

        Public Overrides Sub Down()
            DropTable("dbo.Tests")
        End Sub
    End Class

End Namespace

MetadataType中的EF6迁移精度

0 个答案: