Pass delegate Action<T> explicitly to the method instead of anonymously

Question

Let's say I'm adding a DbContext to services by dependency injection like this :

builder.Services.AddDbContext<AppDbContext>(options =>
    options.UseSqlServer(builder.Configuration.GetConnectionString("DBConnection")));

How do I do that explicitly by providing Action delegate to the AddDbContext method with new Action<> ?

builder.Services.AddDbContext<AppDbContext>(new Action<DbContextOptionsBuilder> ??? );

What to write instead of '???'

Answer 1

You can pass the delegate in multiple ways.
Anonymous lambda (your original)

builder.Services.AddDbContext<AppDbContext>(options =>
    options.UseSqlServer(builder.Configuration.GetConnectionString("DBConnection")));

Manually create an Action<>. But why anyone would want to do that?

var action = new Action<DbContextOptionsBuilder>(options =>
    options.UseSqlServer(builder.Configuration.GetConnectionString("DBConnection")));

builder.Services.AddDbContext<AppDbContext>(action);

Local or regular function

void Configure(DbContextOptionsBuilder options)
{
    options.UseSqlServer(builder.Configuration.GetConnectionString("DBConnection"));
}

builder.Services.AddDbContext<AppDbContext>(Configure);

Action<> as a variable

var configure = (DbContextOptionsBuilder options) => 
{
    options.UseSqlServer(builder.Configuration.GetConnectionString("DBConnection"));
}; 

builder.Services.AddDbContext<AppDbContext>(Configure);