Dictionary.Item[] Property in C#

The Dictionary.Item[] property in C# is used to get or set the value associated with the specified key in the Dictionary.

Syntax

Following is the syntax −

public TValue this[TKey key] { get; set; }

Example

Let us now see an example to implement the Dictionary.Item[] property −

using System; using System.Collections.Generic; public class Demo {    public static void Main(){       Dictionary<string, string> dict =       new Dictionary<string, string>();       dict.Add("One", "Chris");       dict.Add("Two", "Steve");       dict.Add("Three", "Messi");       dict.Add("Four", "Ryan");       dict.Add("Five", "Nathan");       Console.WriteLine("Count of elements = "+dict.Count);       Console.WriteLine("
Key/value pairs...");       foreach(KeyValuePair<string, string> res in dict){          Console.WriteLine("Key = {0}, Value = {1}", res.Key, res.Value);       }       Console.WriteLine("Value for key three = "+dict["Three"]);       dict["Three"] = "Ronaldo";       Console.Write("Updated value associated with key Three...");       Console.WriteLine(dict["Three"]);       if (dict.ContainsValue("Angelina"))          Console.WriteLine("

Value found!");       else          Console.WriteLine("

Value isn't in the dictionary!");       dict.Clear();       Console.WriteLine("Cleared Key/value pairs...");       foreach(KeyValuePair<string, string> res in dict){          Console.WriteLine("Key = {0}, Value = {1}", res.Key, res.Value);       }       Console.WriteLine("Count of elements now = "+dict.Count);    } }

Output

This will produce the following output −

Count of elements = 5 Key/value pairs... Key = One, Value = Chris Key = Two, Value = Steve Key = Three, Value = Messi Key = Four, Value = Ryan Key = Five, Value = Nathan Value for key three = Messi Updated value associated with key Three...Ronaldo Value isn't in the dictionary! Cleared Key/value pairs... Count of elements now = 0

Example

Let us now see another example to implement the Dictionary.Item[] method −

using System; using System.Collections.Generic; public class Demo {    public static void Main(){       Dictionary<string, string> dict =       new Dictionary<string, string>();       dict.Add("One", "Chris");       dict.Add("Two", "Steve");       dict.Add("Three", "Messi");       dict.Add("Four", "Ryan");       dict.Add("Five", "Nathan");       Console.WriteLine("Count of elements = "+dict.Count);       Console.WriteLine("
Key/value pairs...");       foreach(KeyValuePair<string, string> res in dict){          Console.WriteLine("Key = {0}, Value = {1}", res.Key, res.Value);       }       Console.WriteLine("Value for key three = "+dict["Three"]);       dict["Three"] = "Katie";       Console.Write("Updated value associated with key Three...");       Console.WriteLine(dict["Three"]);    } }

Output

This will produce the following output −

Count of elements = 5 Key/value pairs... Key = One, Value = Chris Key = Two, Value = Steve Key = Three, Value = Messi Key = Four, Value = Ryan Key = Five, Value = Nathan Value for key three = Messi Updated value associated with key Three...Katie