c# dictionary key value code example

Example 1: c# dictionaries

IDictionary<int, string> dict = new Dictionary<int, string>();
        
//or

Dictionary<int, string> dict = new Dictionary<int, string>();

Example 2: dictionary c#

IDictionary<int, string> numberNames = new Dictionary<int, string>();
numberNames.Add(1,"One"); //adding a key/value using the Add() method
numberNames.Add(2,"Two");
numberNames.Add(3,"Three");

//The following throws run-time exception: key already added.
//numberNames.Add(3, "Three"); 

foreach(KeyValuePair<int, string> kvp in numberNames)
    Console.WriteLine("Key: {0}, Value: {1}", kvp.Key, kvp.Value);
		
//creating a dictionary using collection-initializer syntax
var cities = new Dictionary<string, string>(){
	{"UK", "London, Manchester, Birmingham"},
	{"USA", "Chicago, New York, Washington"},
	{"India", "Mumbai, New Delhi, Pune"}
};
		
foreach(var kvp in cities)
    Console.WriteLine("Key: {0}, Value: {1}", kvp.Key, kvp.Value);

Example 3: dictionary c#

var cities = new Dictionary<string, string>(){
	{"UK", "London, Manchester, Birmingham"},
	{"USA", "Chicago, New York, Washington"},
	{"India", "Mumbai, New Delhi, Pune"}
};

Example 4: c# dictionary functions

Dictionary<int, Func<string, bool>>