How do I print a dictionary?

Context: Andreas (above) asked the OP about the "exotic" nature of his proposed data-structure. The OP replied: "I know it's really bad, and I'm trying to abstract it a bit because it is really hard to work with."

As best as I can understand it, the OP is using this data-structure:

Dictionary<
    string,
    HashSet<
        Dictionary<
            string,
            HashSet<string>>>>

I think it's useful to try and approach improving a data-structure like this by considering how it would "map" to Classes:

I'd start by defining the nested data-elements from "outermost to innermost:"

// outer Dictionary<string,>
public class OuterD : Dictionary<string, InnerH>
{
    public static StringBuilder sb = new StringBuilder();

    public override string ToString()
    {
        sb.Clear();
        sb.AppendLine("Outer Dictionary:");
        
        foreach (var kvp in this)
        {
            sb.Append("\tKey: ");
            sb.AppendLine(kvp.Key);
            sb.Append("\tValue: ");
            sb.Append(kvp.Value.ToString());
            sb.AppendLine();
        }

        return sb.ToString();
    }
}

// the HashSet which is the Value of the outermost Dictionary
public class InnerH : HashSet<InnerD>
{
    public override string ToString()
    {
        // left for you to write: use the StringBuilder like this:
        OuterD.sb.AppendLine("\t\tHashSet of Outer Dictionary Value Value:");

        foreach (var hshval in this)
        {
            // left for you to write
        }

        return "";
    }
}

// the innermost Dictionary used as elements of the HashSet
public class InnerD : Dictionary<string,HashSet<string>>
{
    public override string ToString()
    {
        // left for you to write: use the StringBuilder like this:
        OuterD.sb.AppendLine("\t\t\tInner Dictionary of Inner HashSet:");

        foreach (var kvp in this)
        {
            OuterD.sb.Append("\t\t\tKey: ");
            OuterD.sb.AppendLine(kvp.Key);
            
            foreach (var hsh in kvp.Value)
            {
                // for you to write
            }
        }

        return "";
    } 
}

What "jumps out" at me looking at the data-structure from this "point-of-view" is that you've got two "levels" of hashing going on here: why do you need two; why can't you just use a Dictionary<string, string> for the innermost Dictionary, and only Hash the Dictionary itself ?

I hope you can see who the task of printing ... if by "printing" you mean rendering the current state of the data-structure into one string ... can be done by overloading 'ToString() in each of the Classes and then essentially "chaining" their calls, while providing a 'static StringBuilder to use to hold the assembling string.