Question

所有

我在使用Entity Framework 5的ASP.NET MVC应用程序中使用工作单元和通用存储库模式进行数据访问。当我只需要处理1个数据库和DbContext时，我的应用程序工作正常。

我的问题是，我有第二个非常密切相关的数据库，我需要数据访问，所以我假设我需要第二个DbContext。但是，我不是＆＃ 39;知道如何重构我的通用存储库以容纳多个DbContext。救命啊！

这里简要介绍了我尝试过的内容，并通过评论解释了哪些内容失败了：

public class UnitOfWork
{
    private Db1Entities db1Context  = new Db1Entities();
    private Db2Entities db2Context = new Db2Entities();

    public GenericRepository<ObjectA> ObjectARepository { // ObjectA is sourced from database 1, so it uses a different DbContext than ObjectB.
        get {
            return new GenericRepository<ObjectA>(db1Context);
        }
    }

    public GenericRepository<ObjectB> ObjectBRepository { // ObjectB is sourced from database 2, so it uses a different DbContext than ObjectA.
        get {
            return new GenericRepository<ObjectB>(db2Context);
        }
    }   
}

public class GenericRepository<T> where T : class
{
    internal DbContext context; // This line and the GenericRepository constructor are my problem. Type DbContext, being a base class, doesn't have the db objects that Db1Entities or Db2Entities have.
                                // When I used to only have to manage 1 DbContext, "context" was type Db1Entities and it worked fine. 
    internal DbSet<T> dbSet;

    public GenericRepository(DbContext context) {
        this.context = context;
        this.dbSet = context.set<T>();
    }

    public virtual T GetByID (int id) {
        // code to return a T object by id...
    }

    // Other repository methods...
}

仅供参考我这是我现在要做的事情。我不认为这是一个解决方案，因为我正在复制＆＃34; GenericRepository＆＃34;通过将其复制为2个通用存储库，每个存储库都设计用于不同的DbContext。我想我应该能够使用＆＃34; GenericRepository＆＃34;并且能够传递DbContext而不是为每个DbContext创建一个GenericRepository类......我只是不知道如何使它工作。见下文：

public class UnitOfWork
{
    private Db1Entities db1Context  = new Db1Entities();
    private Db2Entities db2Context = new Db2Entities();

    public GenericDb1Repository<ObjectA> ObjectARepository { // ObjectA is sourced from database 1, so it uses a different DbContext than ObjectB.
        get {
            return new GenericDb1Repository<ObjectA>(db1Context);
        }
    }

    public GenericDb2Repository<ObjectB> ObjectBRepository { // ObjectB is sourced from database 2, so it uses a different DbContext than ObjectA.
        get {
            return new GenericDb2Repository<ObjectB>(db2Context);
        }
    }   
}

public class GenericDb1Repository<T> where T : class
{
    internal Db1Entities  context; 
    internal DbSet<T> dbSet;

    public GenericRepository(Db1Entities context) {
        this.context = context;
        this.dbSet = context.set<T>();
    }

    public virtual T GetByID (int id) {
        // code to return a T object by id...
    }

    // Other repository methods...
}

public class GenericDb2Repository<T> where T : class
{
    internal Db2Entities  context; 
    internal DbSet<T> dbSet;

    public GenericRepository(Db2Entities context) {
        this.context = context;
        this.dbSet = context.set<T>();
    }

    public virtual T GetByID (int id) {
        // code to return a T object by id...
    }

    // Other repository methods...
}

Answer 1

    public class GenericDb1Repository<T, TContext> 
    where T : class
    where TContext : DbContext, new()
{
    internal TContext context; 
    internal DbSet<T> dbSet;

    public GenericRepository(TContext context) {
        this.context = context;
        this.dbSet = context.set<T>();
    }

    public virtual T GetByID (int id) {
        // code to return a T object by id...
    }

    // Other repository methods...
}**

实体框架5 - 多个DbContext和一个通用存储库类

1 个答案: