C# 为什么`DatabaseGenerated(DatabaseGeneratedOption.Identity)` 在MVC 4 中不起作用
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Why `DatabaseGenerated(DatabaseGeneratedOption.Identity)` doesn't work in MVC 4
提问by ahmadali shafiee
I was trying to move my MVC 3 project to MVC 4 but when I wanted to move this model:
我试图将我的 MVC 3 项目移动到 MVC 4 但是当我想移动这个模型时：
public class Link
{
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public Guid ID { get; set; }
[DisplayName("Shorted URL")]
public string SURL { get; set; }
[DisplayName("General Link")]
public string OriginalURL { get; set; }
[DisplayName("Click Count")]
public int ClickCount { get; set; }
}
public class LinkDBContext : DbContext
{
public DbSet<Link> Links { get; set; }
}
I got error with [System.ComponentModel.DataAnnotations.(DatabaseGeneratedOption.Identity)]attribute. I don't know what's the problem. Does anyone know?!?
我有[System.ComponentModel.DataAnnotations.(DatabaseGeneratedOption.Identity)]属性错误。我不知道有什么问题。有人知道吗？！？
Update
更新
These are the errors:
这些是错误：
The type or namespace name 'DatabaseGeneratedAttribute' could not be found (are you missing a using directive or an assembly reference?)
The type or namespace name 'DatabaseGenerated' could not be found (are you missing a using directive or an assembly reference?)
找不到类型或命名空间名称“DatabaseGeneratedAttribute”（您是否缺少 using 指令或程序集引用？）
找不到类型或命名空间名称“DatabaseGenerated”（您是否缺少 using 指令或程序集引用？）
采纳答案by Erik Funkenbusch
DatabaseGeneratedAttributeis in the
System.ComponentModel.DataAnnotations.Schemanamespace attribute in .NET 4.5
DatabaseGeneratedAttributeSystem.ComponentModel.DataAnnotations.Schema位于 .NET 4.5的
命名空间属性中
回答by Mahmoodvcs
If you want to use this attribute in .net 4 you can use Prerelease version of EntityFramework 6 (or even Nightly Builds) to do this, in Manage NuGet Pakageswindow, from the drop-down on top of the window, select Include Prerelease.
如果你想在 .net 4 中使用这个属性，你可以使用 EntityFramework 6 的 Prerelease 版本（甚至 Nightly Builds）来做到这一点，在Manage NuGet Pakages窗口中，从窗口顶部的下拉菜单中，选择Include Prerelease。
To update to Nightly Builds, in Pakage Manager Settingsadd this Package Source:
要更新到 Nightly Builds，请Pakage Manager Settings添加此包源：
http://www.myget.org/F/aspnetwebstacknightly/
For a complete guide, see EF on GitHub.
有关完整指南，请参阅GitHub 上的 EF。
回答by d4c0d312
You need - in some cases - to change the framework from 4.5 or less to 4.5.1 and then install Entity Framework 6 + and it will be found
您需要 - 在某些情况下 - 将框架从 4.5 或更低版本更改为 4.5.1，然后安装 Entity Framework 6 +，它将被找到
