DictionaryEntry

This C# type is used with Hashtable. The Hashtable collection provides a way to access objects based on a key. We use DictionaryEntry in a foreach-loop.

Type notes

Usually DictionaryEntry is part of a foreach-loop, but it can be used to store pairs together. This is similar to a KeyValuePair or Tuple.

Foreach example

This example uses the Hashtable type and instantiates it upon the managed heap. Then 3 key-value pairs are added to the Hashtable instance.

using System;
using System.Collections;

// Create Hashtable with some keys and values.
Hashtable hashtable = new Hashtable();
hashtable.Add(1, "one");
hashtable.Add(2, "two");
hashtable.Add(3, "three");

// Enumerate the Hashtable.
foreach (DictionaryEntry entry in hashtable)
{
    Console.WriteLine("{0} = {1}", entry.Key, entry.Value);
}
3 = three
2 = two
1 = one

Class example

DictionaryEntry is not tied to the Hashtable collection. You can create an instance to store a key-value pair anywhere.

using System;
using System.Collections;

class Program
{
    static DictionaryEntry GetData()
    {
        // Return DictionaryEntry as key-value pair.
        return new DictionaryEntry("cat", "frog");
    }

    static void Main()
    {
        var data = GetData();
        Console.WriteLine(data.Key);
        Console.WriteLine(data.Value);
    }
}
cat
frog

A summary

To loop over a C# Hashtable collection, you can use the foreach-loop statement. Then access the properties on each DictionaryEntry.

Final note

The DictionaryEntry struct is not a class, and is stored on the stack when used as a local variable. It can be instantiated anywhere in C# programs.