Show more examples of obtaining and setting connection strings

[bdaniel7]

What if I need to use a connection string from the config file? like, you know,

public ApplicationDbContext CreateDbContext(string[] args)
{
	var builder = new DbContextOptionsBuilder<ApplicationDbContext>();

	builder.UseSqlServer( --> Configuration.GetConnectionString("DefaultConnection") <-- );

	return new ApplicationDbContext(builder.Options);
}

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Document Details

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• ID: 2fa64390-1232-8dd3-f170-7d5c68e29ad9
• Version Independent ID: 245bbba8-3102-4a66-15eb-650e05eb9e62
• Content: Design-time DbContext Creation - EF Core
• Content Source: entity-framework/core/miscellaneous/cli/dbcontext-creation.md
• Product: entity-framework
• GitHub Login: @bricelam
• Microsoft Alias: bricelam

[Advanium]

Hey @bdaniel7!

You could add the code for acquiring a connection string inside the CreateDbContext method. Have a look into issue https://github.com/aspnet/EntityFrameworkCore/issues/8332 where others were facing the same problem and provided their solution.

Cheers, René

[bproven]

Helpful, but why not update the docs HERE with a real world example.

[DHclly]

I use json.net and File.ReadAllText to load config in appsettings.json

public EFContext CreateDbContext(string[] args)
        {
            var text = File.ReadAllText(Path.Combine(AppContext.BaseDirectory, "appsettings.json"));
            var config = JsonConvert.DeserializeObject(text) as JObject;
            var connectionString = config["ConnectionStrings"]["SqliteConn"].ToString();
            var optionsBuilder = new DbContextOptionsBuilder<EFContext>();
            optionsBuilder.UseSqlite(connectionString);
            return new EFContext (optionsBuilder.Options);
        }