BinarySearch in two dimensional list

Question

I have dimensional list:

List<List<string>> index_en_bg = new List<List<string>>();

   index_en_bg.Add(new List<string>() { word1, translation1 }); 
   index_en_bg.Add(new List<string>() { word2, translation2 }); 
   index_en_bg.Add(new List<string>() { word3, translation3 });

I would do binary search by the first column (words), something like this:

int row = index_en_bg.BinarySearch(searchingstr);

but it works only for a one-dimensional list. How would I extend it to work for two-dimensional lists in my case? I don't want to use Dictionary class.

Answer 1

In this case you need to provide your own customer IComparer-implementing comparator

public class Comparer: IComparer<IList<string>>
{
    public int Compare(IList<string> x, IList<string> y)
    {
        // base the comparison result on the first element in the respective lists
        // eg basically
        return x[0].CompareTo(y[0]);
    }

And you'll call it like this, offering a List where only the field you're searching is filled in.

int row = index_en_bg.BinarySearch(new List<string>() {searchingstr},new Comparer());