Pass and instance to a method with Action as parameter

Question

I have the following method:

IdentityBuilder IServiceCollection.AddIdentityCore<User>(Action<IdentityOptions> setupAction)

Which I use as follows:

  services.AddIdentityCore<User>(x => {
    x.Password.RequiredLength = 8;
  })

This works but I tried to create a class with default values:

public class IdentityDefaultOptions : IdentityOptions {
  public IdentityDefaultOptions() {
    Password.RequiredLength = 8;
  }
}

And use it as follows:

services.AddIdentityCore<User>(x => new IdentityOptions())

It compiles but Password.RequiredLength is not applied.

What am I missing?

Answer 1

You are simply creating a new instance that will never be used. It is doing something like this:

public void Test(IdentityOptions options)
{
   new IdentityOptions()
}

That makes no sense at all.

Instead, you have to interact with the x object and set its values. It would be equals to:

public void Test(IdentityOptions options)
{
   options.Password.RequiredLength = 8;
}

You might take a look at the delegate, anonymous methods and lambda and '=>' operator documentation