Question

I am trying to make a 1d array of lists. I make it like this:

public static List<string>[] words = new List<string>[30];
public static List<string>[] hints = new List<string>[30];

And I call it like this:

foreach (string item in vars.directory)
        {
            reader2 = new StreamReader(item);
            while (reader2.Peek() > 0)
            {
                string line = reader2.ReadLine();
                if (line.StartsWith("#"))
                {
                    vars.words[counter].Add(line.Substring(1, line.Length - 1)); //here
                }
                else if (line.StartsWith("-"))
                {
                    vars.hints[counter].Add(line.Substring(1, line.Length - 1)); //another here
                }
                else if (line == "@end")
                {
                    counter++;
                }
            }
        }

I just wanted to add that vars is where I keep my public variables and that counter is indeed at 0 when the loop starts.

EDIT
In my haste I forgot to add the question… oops…

Here it is: When I call the add function (or any another function for that matter) it returns a null reference exception. How can I fix this?

Answer 1

I assume you’re crashing when attempting to call .Add on your array element. You need to initialize your arrays with valid objects.

for( Int32 i = 0; i < vars.words.Length; ++i )
  vars.words[i] = new List<string>();
for( Int32 i = 0; i < vars.hints.Length; ++i )
  vars.hints[i] = new List<string>();