C# Sortable collection which allows duplicate keys

Question

I am writing a program to set a sequence in which various objects will appear in report. The sequence is the Y position (cell) on Excel spreadsheet.

A demo part of co

Answer 1

The problem is that the data structure design doesn't match the requirements: It is necessary to store several Headers for the same XPos. Therefore, SortedList should not have a value of Header, but a value of List

. It's a simple and small change, but it solves all problems and avoids creating new problems like other suggested solutions (see explanation below):

using System;
using System.Collections.Generic;

namespace TrySortedList {
  class Program {

    class Header {
      public int XPos;
      public string Name;
    }

    static void Main(string[] args) {
      SortedList> sortedHeaders = new SortedList>();
      add(sortedHeaders, 1, "Header_1");
      add(sortedHeaders, 1, "Header_2");
      add(sortedHeaders, 2, "Header_3");
      foreach (var headersKvp in sortedHeaders) {
        foreach (Header header in headersKvp.Value) {
          Console.WriteLine(header.XPos + ": " + header.Name);
        }
      }
    }

    private static void add(SortedList> sortedHeaders, int xPos, string name) {
      List
 headers;
      if (!sortedHeaders.TryGetValue(xPos, out headers)){
        headers = new List
();
        sortedHeaders[xPos] = headers;
      }
      headers.Add(new Header { XPos = xPos, Name = name });
    }
  }
}

Output:
1: Header_1
1: Header_2
2: Header_3

Please note that adding a "funny" key, like adding a random number or pretending that 2 XPos with the same value are different lead to many other problems. For example it becomes difficult or even impossible to remove a particular Header.

Also note that the sorting performance is much better if only few List

have to be sorted than every Header. Example: If there are 100 XPos and each has 100 headers, 10000 Header need to be sorted as opposed to 100 List

.

Of course, also this solution has a disadvantage: If there are many XPos with only 1 Header, as many Lists need to be created, which is some overhead.