Dictionary out of a complex nested object-CodePudding

I have DTOs like this

public class Obj1
{
    public string a1 { get; set; };
    public Obj2[] a2 { get; set; };
}
public class Obj2
{
    public string b1 { get; set; };
    public Obj3[] b2 { get; set; };
}
public class Obj3
{
    public string Key  { get; set; };
}

So, the object will be like

Obj1 o = new Obj1
{
    a1="a";
    a2=new[]
    {
        new Obj2
        {
            b1="b";
            b2=new[]
            {
                new Obj3
                {
                   Key="c";
                }
            }
        }
    }
}

I have Obj1. How can I group it in the form of dictionary of type

IDictionary<string, IEnumerable<Obj2>>

where Key is in Obj3.

I tried using GroupBy but did not get the relevant result.

CodePudding user response：

If I understand the end goal - co combine all Obj2 by all child Obj3.Key and after fixing the code to make it compile you can use SelectMany into intermediate data structure with aggregation with GroupBy:

var dictionary = o.a2
    .SelectMany(o2 => o2.b3.Select(o3 => (o3.Key, o2)))
    .GroupBy(t => t.Key)
    .ToDictionary(g => g.Key, g => g.ToList());

CodePudding user response：

Im not quite sure, but your class "obj2" instead of having 2 properties, you can make it with one property of Dictionary with a string key and Ienumerable value, so your variable could look like this. Dictionary<string, Dictionary<string, Ienumerable>> and you can add "obj3" as a value or key.