Change Connection String at Runtime in EF 6

Question

I mostly use my dbcontext with using statements like this:

using (var context = new MyContext())
{
}

But I later had to add a project with a function to change the database. I found out that I could change my dbcontext constructor to this:

public MyContext(string connectionstring)
        : base(connectionstring)
{
}

I made a class with a property for the connectionstring:

public static class DbAccessor
{
    public static string ConnectionStringForContext { get; set; }
}

I set this property in the beginning and my using statements look like this:

using (var context = new MyContext(DbAccessor.ConnectionStringForContext) 
{}

It works, but my connection string is now everywhere and I feel like I should not do that with connection strings. Is there a better way of doing this? What would be the best way to handle my Connection Strings if I want to change them? Should I stop using these using statements?

I've seen this question: Entity Framework change connection at runtime

But the difference is, that I have a functioning solution, but I don't want to have my connection string everywhere. If I used that extension method inside every using statement. It would almost be like my solution just one line more in every using statement...

Answer 1

You could try a static factory method (or factory class whichever you prefer) on your context which uses the connection string like so:

public class MyContext : ...
{
    public MyContext(string connectionstring)
        : base(connectionstring)
    {
    }

    public static MyContext Create()
    {
        return new MyContext(DbAccessor.ConnectionStringForContext);
    }
}

and then you can create your context like so:

using (var context = MyContext.Create())
{
}