How can I go through different levels in a dictionary

Question

I've been reading a lot of documentation on how to iterate a Dictionary with a foreach, but I don't quite understand how I can go through the levels it has. For example:

I have "params" Dictionary, I add string and object values ​​to it, with .Add(), and to one of them I add a level called "item".

From what I understand, with the Foreach(KeyValueaPair<>) it is to iterate through the Dictionary. Do I need to use another foreach(KeyValuePair<>) to be able to loop through the second level?

For example, I want "param" to get the value of the element that Posnr brings

 IDictionary<string, object> params = new Dictionary<string, object>();

            params.Add("Customerid", zwCustomer.Customerid);
            params.Add("PedidoCli", zwCustomer.PedidoCli);
            params.Add("PedidoSap", zwCustomer.PedidoSap);

            params.Add("TFacturaMat", new Dictionary<string, object>()
            {
                {
                    "item", new Dictionary<string, object>()
                    {
                        {"Vbeln", zfacturaMats.Vbeln},
                        {"Posnr", zfacturaMats.Posnr},
                        {"Matnr", zfacturaMats.Matnr},
                    }
                },
            });

           foreach(KeyValuePair<string, object> item in parametros)
           {
                param = $"{item.Key} : {item.Value}";
           }

Answer 1

No, you can do that directly. The Dictionary<TKey, TValue> class of the .NET library already does all that magic for you.

With the foreach loop

           foreach(KeyValuePair<string, object> item in params)
           {
                Console.WriteLine($"{item.Key} : {item.Value}");
           }

you already iterate trough all the elements of your dictionary. From an usage point of view this works exactly the same as if params was a List (except that there's no guaranteed order).

If you want a particular element, you have multiple possibilities, but in the easiest case you can just get an element by var myValue = params["PosNr"]. Alternatively you can use the TryGetValue() method to test whether a certain key is present.

So bottom line: It's interesting to know how a dictionary works internally, but when you use the .NET libraries, you don't have to care about that. Iterating and accessing works just out of the box.