Question

我设法完成了这项工作并更新了以下内容以展示我是如何做到的。如果有更优雅的解决方案，我感兴趣：）

前言：我正试图从Entity Framework 6迁移到Entity Framework Core。我有一个现有的数据库。我正在做数据库第一代。我使用＆＃34; scaffold-dbContext＆＃34;生成类。在控制台中执行此命令。好的，没关系。但是我希望所有生成的类都从一个简单的基类继承。这是整个基类的要点：

public class MyEntityBase
{
    public MyEntityBase()
    {
    }
}

因此，如果数据库中有一个名为customer的表，我希望生成的类开始于：

public partial class Customer : MyEntityBase

我可以通过更改相应位置的T4文件在EF6中执行此操作。我设法通过以下方式在EF Core中完成。

首先获得更多信息。在我的解决方案中，我有两个项目。一个是＆＃34; Web＆＃34; project，作为ASP.NET Core Web应用程序创建的。另一个是＆＃34;核心＆＃34; project，创建为.NET Core类库。这是Context文件和实体类将存在的位置。它也是MyEntityBase生活的地方。

好的，我在Web项目中添加了一个名为MyDesignTimeServices.cs的类文件。该文件的内容如下：

using System;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.EntityFrameworkCore.Infrastructure;
using Microsoft.EntityFrameworkCore.Scaffolding.Internal;
using Microsoft.EntityFrameworkCore.Scaffolding.Configuration.Internal;

namespace MySolution.Web
{
public class MyDesignTimeServices : IDesignTimeServices
{
    public void ConfigureDesignTimeServices(IServiceCollection serviceCollection)
    {
        //serviceCollection.AddSingleton<EntityTypeWriter, MyEntityTypeWriter>();
        serviceCollection.AddSingleton<DbContextWriter, MyDbContextWriter>();
    }
}

public class MyDbContextWriter : DbContextWriter
{
    public MyDbContextWriter(ScaffoldingUtilities scaffoldingUtilities, CSharpUtilities cSharpUtilities) : base(scaffoldingUtilities, cSharpUtilities) { }

    public override string WriteCode(ModelConfiguration modelConfiguration)
    {
        var code = base.WriteCode(modelConfiguration);
        code = code.Replace("});", "\tentity.HasBaseType<" + typeof(MySolution.Core.MyEntityBase).Name + ">();" + Environment.NewLine + "\t\t\t});");
        return code;
    }
}

public class MyEntityTypeWriter : EntityTypeWriter
{
    public MyEntityTypeWriter(CSharpUtilities cSharpUtilities) : base(cSharpUtilities) { }

    public override string WriteCode(EntityConfiguration entityConfiguration)
    {
        // Get the default code of the entity class.
        var code = base.WriteCode(entityConfiguration);

        // We need to find the spot after the name of the class so we can add its inheritance.
        var classDeclaration = "public partial class ";
        var classDeclarationIndex = code.IndexOf(classDeclaration);
        if (classDeclarationIndex != -1)
        {
            // Remove anything in front of the class name, so that we can look for the first carriage return.
            var startsWithClassName = code.Substring(classDeclarationIndex + classDeclaration.Length);
            var afterClassNameIndex = startsWithClassName.IndexOf((char)13);
            if (afterClassNameIndex != -1)
            {
                // This is the spot where we want to insert our inheritance declaration.
                var insertIndex = classDeclarationIndex + classDeclaration.Length + afterClassNameIndex;

                // Insert our inheritance declaration.
                code = code.Substring(0, insertIndex) + " : " + typeof(MyEntityBase.Core.MyEntityBase).Name + code.Substring(insertIndex);
            }
        }

        return code;
    }
}
}

构建解决方案。然后，当我在包管理器控制台中运行Scaffold-DbContext命令时，我确保将Default project下拉选项设置为Core项目。

.NET Core Entity Framework数据库首先生成要从基类

0 个答案: