实体框架DDD

Question

I work on a EF Core project for WPF app. We decide to split the DbContext in 2 smallers : (the project contains a single Database)

public class FirstDbContext : DbContext
{
    public DbSet<Blog> Blogs { get; set; }  
    public DbSet<Post> Posts { get; set; }
    public DBSet<Parameters>{ get; set; }            
}

public class SecondDbContext: DbContext
{
    public DBSet<User>{ get; set; }
    public DBSet<Books> { get; set; }
    public DBSet<Parameters>{ get; set; }  
}

and we keep a "super" DbContext (wich contains all the DbSets from the DB) to maintain and migrate the DB

public class SuperDbContext : DbContext
{
    public DbSet<Blog> Blogs { get; set; }  
    public DbSet<Post> Posts { get; set; }
    public DBSet<User>{ get; set; }
    public DBSet<Books> { get; set; }
    public DBSet<Parameters>{ get; set; }  
}....

The first step to refactore code is to replace the lines wich references the "SuperDbContext..." with the correct call "SecondDbContext.Books..."or "FirstDbContext.Post"... OK

Question : In the Client app, the choice of DbContext is depending about a user's choice when app is launching : if user choose option1 => FirstDbContext, and if option2 => SecondDbContext.

How can we write the code to switch on the current DbContext to manage the "common DbSet" (Parameters) : before refactoring we have for example : SuperDbContext.Parameters.FirstOrDefault()... and now ? do we have to write something like this :

if(option1)
{
    FirstDbContext.Parameters.First()
}else
{
    SecondDbContext.Parameters.First() 
}

And what is the impact in the repositories ? cause if we maintain this approach we have to duplicate code in the 2 Repositories :-( ?

Answer 1

No no... Forget about the approach you mentioned, you'll end up writing twice the code you need. Why don't you just use db context type :

At the beginning of your function, a single if else :

DbContext context;

if(option1)
{
    context = new firstContextEntities();
}
else
{
    context = new secondContextEntities();
}

And as both of your contexts are almost exactly the same, you will use your context by casting it to the greater one (the one that has the most access) :

var FirstLine = ((secondContextEntities)context).Parameters.First();