Sort KeyValuePair List. A List contains many KeyValuePair struct instances. It can be sorted with the Sort List method. For advanced sorting, we need Comparison.

Comparison info. This code requires Comparison delegate implementations. We implement these as static int methods that call CompareTo.

Comparison

CompareTo

Sort

Example code. Compare1 receives two KeyValuePair structs and returns the result of CompareTo on their Key. Compare2 returns the CompareTo of the Value.

KeyValuePair

List

Console.WriteLine

using System;
using System.Collections.Generic;

class Program
{
    static int Compare1(KeyValuePair<string, int> a, KeyValuePair<string, int> b)
    {
        return a.Key.CompareTo(b.Key);
    }

    static int Compare2(KeyValuePair<string, int> a, KeyValuePair<string, int> b)
    {
        return a.Value.CompareTo(b.Value);
    }

    static void Main()
    {
        var list = new List<KeyValuePair<string, int>>();
        list.Add(new KeyValuePair<string, int>("Perl", 7));
        list.Add(new KeyValuePair<string, int>("Net", 9));
        list.Add(new KeyValuePair<string, int>("Dot", 8));

        // Use Compare1 as comparison delegate.
        list.Sort(Compare1);

        foreach (var pair in list)
        {
            Console.WriteLine(pair);
        }
        Console.WriteLine();

        // Use Compare2 as comparison delegate.
        list.Sort(Compare2);

        foreach (var pair in list)
        {
            Console.WriteLine(pair);
        }
    }
}
[Dot, 8]
[Net, 9]
[Perl, 7]

[Perl, 7]
[Dot, 8]
[Net, 9]

Program results. The List.Sort(Compare1) call sorts the List by the Key of the KeyValuePair. And the List.Sort(Compare2) call sorts the List by the Value int.

Sort List, Lambda

Compare1 -> Key
Compare2 -> Value

A summary. We sorted collections of KeyValuePairs. We can use other syntax forms and implementations, such as LINQ expressions or lambda expressions, to accomplish this task.

orderby

Lambda