How to get context based on database type?

Question

I have two Context as you see below.

public class AddressContext:DbContext{

    public AddressContext()
    {
        Name = "AddressContext";

    }
    public DbSet<address> addresses { get; set; }
}

public class NamesContext:DbContext{
    public NamesContext()
    {
        Name = "NamesContext";
    }
     public DbSet<Names> names { get; set; }
}

I also added enum for DatabaseType.

public enum DatabaseType
{
    address,
    names 
}

I would like to get Context based on DatabaseType.

I am not very familiar with the Factory or Strategy pattern in C#. I did try to write it but at the end I have to cast that context in order to use it.

What is the best way to get Context based on passing DatabaseType as parameter?

Factory pattern is used when all the concrete instances of different types have the same interface but implemented differently. In this case you have 2 classes having different members so it of course requires casting later. What you want here is impossible without casting **unless** somehow you just want to use some ***common members*** via an interface. Then all the classes should implement that interface and then you don't need casting. — Hopeless, Sep 17 '15 at 00:00

score 0 · Accepted Answer · answered Sep 16 '15 at 22:41

0

public DbContext GetContext(DatabaseType dbType)
{
    switch(dbType)
    {
        case DatabaseType.address:
            return new AddressContext();
        case DatabaseType.names:
            return new NamesContext();
        default:
            throw new ArgumentException("Unexpected db type.");
    }
}

answered Sep 16 '15 at 22:41

Mark Seemann

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let's say i called `DbContext context = GetContext(DatabaseType.address);` I am still not able to access `address` property. – dev Sep 16 '15 at 22:53
@Mvcdev That's correct. `DbContext` doesn't define that property. – Mark Seemann Sep 16 '15 at 22:55
I want to access those property that assign in context. What is the best way to get those property? – dev Sep 16 '15 at 22:57
@Mvcdev Program against the concrete types. – Mark Seemann Sep 16 '15 at 22:59
could you please elaborate your above answer? – dev Sep 16 '15 at 23:07
@Mvcdev This might be useful http://stackoverflow.com/questions/383947/what-does-it-mean-to-program-to-an-interface/384067#384067 – Irshad Sep 17 '15 at 04:48

How to get context based on database type?

1 Answers1