问题描述

是否可以扩展 Entity Framework 6.1.3 生成的类?

Is it possible to extend an Entity Framework 6.1.3 generated class?

我有一个现有的数据库，我在其中创建了一个 ADO.NET 实体数据模型，而 Visual Studio 2015 又生成了一组类.

I have an existing database to which I have created an ADO.NET Entity Data Model, which in turn Visual Studio 2015 has generated a set of classes.

public partial class WebApplication1Entities : DbContext
{
    public WebApplication1Entities()
        : base("name=WebApplication1Entities")
    {
    }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        throw new UnintentionalCodeFirstException();
    }
}

我可以手动覆盖 WebApplication1Entities 以允许动态运行时连接:

I can manually override the WebApplication1Entities to allow a dynamic runtime connection as so:

    public WebApplication1Entities(string connectionString) : base(connectionString)
    {
    }

然而，这涉及编辑 Visual Studio 2015 生成的类，但如果我希望将来更新 ADO.NET 实体数据模型，Visual Studio 将覆盖我对之前生成的类所做的任何手动更改，并且我回到第一方，不得不手动编辑生成的类.

This however, involves editing the class that Visual Studio 2015 has generated, but should I wish to update the ADO.NET Entity Data Model in the future, Visual Studio will overwrite any manual changes I have made to the previous generated class and I'm back to square one, having to manually edit the generated class.

是否可以创建一个帮助类或类似的东西来扩展现有的 WebApplication1Entities : DbContext，并允许添加新的重载方法并继承 Visual Studio 2015 生成的现有方法类，例如虚拟 DbSets.

Is it possible to create a helper class or something similar to extend the existing WebApplication1Entities : DbContext, and allow the addition of the new overloaded method and also inherit the existing methods of the Visual Studio 2015 generated class such as virtual DbSets.

任何帮助将不胜感激:-)

Any help would be much appreciated :-)

推荐答案

正如你在声明中看到的

public partial class WebApplication1Entities : DbContext

这个类是partial.

因此您可以创建另一个 *.cs 文件并将您的代码放在那里(使用相同的命名空间！):

So you can create another *.cs file and put your code there (use the same namespace!):

public partial class WebApplication1Entities
{
     public WebApplication1Entities(string connectionString) : base(connectionString)
     {
     }        
}

因此，当设计器覆盖包含原始"类的文件时，您的代码将保持不变.

So when the designer overwrites the file containing the "original" class, your code stays untouched.

更多关于partial类和方法.

这篇关于如何扩展 Entity Framework 6.1.3 生成的类?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持编程学习网！