c# - 使用 Entity Framework Code First 在数据库中存储 System.Version

Question

我有一个使用 Entity Framework 6.1 Code First 创建的数据库，我有一个特定的表有问题。

我有一个名为Manifests的表，下面是实体定义

public class Manifest
{
    public int Id { get; set; }
    public DateTime ReleaseDate { get; set; }
    public int VersionMajor { get; set; }
    public int VersionMinor { get; set; }
    public int VersionBuild { get; set; }
    public int VersionRevision { get; set; }
    public Version Version
    {
        get
        {
            return new Version(this.VersionMajor, this.VersionMinor, this.VersionBuild, this.VersionRevision);
        }

        set
        {
            this.VersionMajor = value.Major;
            this.VersionMinor = value.Minor;
            this.VersionBuild = value.Build;
            this.VersionRevision = value.Revision;
        }
    }
    public string ReleaseNotes { get; set; }
    public bool IsCompulsory { get; set; }
    public string Description { get; set; }
    public string UpdatePackage { get; set; }
}

您会注意到我定义了一个属性，它是一个 System.Version并将存储 list 版本，但是，当我在包管理器控制台中运行 add-migration 时，生成的迁移不包括 Version柱子。我试过设置 modelBuilder.ComplexType<System.Version>()在 OnModelCreating但无济于事，请帮忙？

按照建议我已经更改了实体定义(见上文)，但我现在在运行种子时遇到错误，请见下文:

System.Data.Entity.Core.EntityCommandCompilationException: An error occurred while preparing the command definition. See the inner exception for details. ---> System.Data.Entity.Core.MappingException: 
(6,10) : error 3004: Problem in mapping fragments starting at line 6:No mapping specified for properties Manifest.Version in Set Manifests.
An Entity with Key (PK) will not round-trip when:
  Entity is type [Drogo.Meera.Data.Context.Manifest]

种子方法有以下内容:

context.Manifests.AddOrUpdate(
    p => p.Version,
    new Manifest
        {
            Description = "Initial Release",
            VersionMajor = 1,
            VersionMinor = 0,
            VersionBuild = 0,
            IsCompulsory = true,
            ReleaseDate = DateTime.Now,
            ReleaseNotes = "Initial Release",
            UpdatePackage = @"v1-0-0\v1-0-0.zip"
        });
context.SaveChanges();

Answer 1

我认为当您将 System.Version 用作复杂类型时，您没有看到预期的结果，因为它没有可供 EF 使用的任何有效属性。

If a property has only a getter or a setter, but not both, it will not be included in the model.

https://www.safaribooksonline.com/library/view/programming-entity-framework/9781449317867/ch05s07.html

---

您应该能够通过提取您想要自己保留的属性(并将 Manifest.Version 标记为要忽略的属性)来解决此问题。

public class Manifest
{
    // other properties

    int VersionMajor { get; set; }
    int VersionMinor { get; set; }
    int VersionBuild { get; set; }
    int VersionRevision { get; set; }

    public Version Version 
    {
        get 
        { 
            return new Version(VersionMajor, VersionMinor, VersionBuild, VersionRevision); 
        }
        set
        {
            VersionMajor = value.Major;
            VersionMinor = value.Minor;
            VersionBuild = value.Build;
            VersionRevision = value.Revision;
        }
    }
}

// Adding [NotMapped] to Manifest.Version would also work, as in the link below
modelBuilder.Entity<Manifest>().Ignore(m => m.Version);

这里还有另一个例子:Entity Framework map multiple columns to C# complex type