Question

I don’t know if this is possible at all so this is a shot in the dark.

Anyhow…

Consider having the following model:

    Class Model
    {
        public List<string> TheList = null;
    }

The List is set to null on purpose.

    var model = new Model();
    command.RegisterInData( model => model.TheList ); // TheList is null at this point

    model.TheList = new List<string>();
    model.TheList.Add("A value here");

    command.Execute(); // <-- Here I want to access the new list somehow

As said, I don’t know if anything like this is possible but I would like a push in the right direction.

The function desired: I would like to tell the command where to put the result before I have a concrete object.

Thanks in advance

Answer 1

This seems quite doable. Here is a variation with an even simpler accessor:

class Command
{
    private Func<List<string>> listAccessor;

    public void RegisterInData(Func<List<string>> listAccessor)
    {
        this.listAccessor = listAccessor;
    }

    public void Execute()
    {
        var list = this.listAccessor();
        foreach (string s in list)
        {
            Console.Log(s);
        }
    }
}

// Elsewhere
var model = new Model();
command.RegisterInData(() => model.TheList);

model.TheList = new List<string>();
model.TheList.Add("A value here");

command.Execute();

You’ll probably want error handling for the case where RegisterInData is not called before Execute, but you get the idea.