Question

I am sitting here finding myself writing a recursive call for C# to write a RegistryKey.

This is something I could hard code easily enough, but I’d to do it recursively.

using System;
using System.Collections.Generic;
using Microsoft.Win32;

private const string regKeyPath = @"Software\Apps\jp2code\net\TestApp";

static void Main() {
  string[] split = regKeyPath.Split('\\');
  RegistryKey key = null;
  try {
    keyMaker(Registry.LocalMachine, split);
  } finally {
    if (key != null) {
      key.Close();
    }
  }
  // continue on with Application.Run(new Form1());
}

So, keyMaker is what I want to be my recursive function.

private static void keyMaker(RegistryKey key, string[] path) {
  string subKey = null;
  string[] subKeyNames = key.GetSubKeyNames();
  foreach (var item in subKeyNames) {
    if (path[0] == item) {
      subKey = item;
    }
  }
  RegistryKey key2 = null;
  try {
    if (String.IsNullOrEmpty(subKey)) {
      key2 = key.CreateSubKey(subKey);
    } else {
      key2 = key.OpenSubKey(subKey);
    }
    keyMaker(key2, &path[1]); // <= NOTE! Not allowed/defined in C#
  } finally {
    key2.Close();
  }
}

So, I can’t simply pass the array starting with the next element of the array.

Is there a neat way to do this in C#?

The Registry bit has nothing to do with the problem but to add my real world problem to an array task.

Answer 1

A simple way to be to change your method’s signature to include the starting index:

void keyMaker(RegistryKey key, string[] path, int startIndex)

Apart from that, you can use a LinkedList<T> or a Queue<T> instead of an array, and use LinkedList<T>.RemoveFirst() or Queue<T>.Dequeue() methods to remove their head elements.

But you don’t need recursion to solve this at all (unless this is an exercise).