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

Updated on: 12-Nov-2019

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