Check if ListDictionary contains a specific key in C#

To check if ListDictionary contains a specific key, the code is as follows −

Example

 Live Demo

using System;
using System.Collections;
using System.Collections.Specialized;

public class Demo {
   public static void Main() {
      ListDictionary dict1 = new ListDictionary();
      dict1.Add("A", "Books");
      dict1.Add("B", "Electronics");
      dict1.Add("C", "Smart Wearables");
      dict1.Add("D", "Pet Supplies");
      dict1.Add("E", "Clothing");
      dict1.Add("F", "Footwear");
      Console.WriteLine("ListDictionary1 elements...");
      foreach(DictionaryEntry d in dict1) {
         Console.WriteLine(d.Key + " " + d.Value);
      }
      ListDictionary dict2 = new ListDictionary();
      dict2.Add("1", "One");
      dict2.Add("2", "Two");
      dict2.Add("3", "Three");
      dict2.Add("4", "Four");
      dict2.Add("5", "Five");
      dict2.Add("6", "Six");
      Console.WriteLine("
ListDictionary2 key-value pairs...");
      IDictionaryEnumerator demoEnum = dict2.GetEnumerator();
      while (demoEnum.MoveNext())
      Console.WriteLine("Key = " + demoEnum.Key + ", Value = "+ demoEnum.Value);
      Console.WriteLine("Is the ListDictionary having fixed size? = "+dict2.IsFixedSize);
      Console.WriteLine("If ListDictionary read-only? = "+dict2.IsReadOnly);
      Console.WriteLine("Is ListDictionary synchronized = "+dict2.IsSynchronized);
      Console.WriteLine("The ListDictionary has the key 5? = "+dict2.Contains("5"));
   }
}

Output

This will produce the following output −

ListDictionary1 elements...
A Books
B Electronics
C Smart Wearables
D Pet Supplies
E Clothing
F Footwear
ListDictionary2 key-value pairs...
Key = 1, Value = One
Key = 2, Value = Two
Key = 3, Value = Three
Key = 4, Value = Four
Key = 5, Value = Five
Key = 6, Value = Six
Is the ListDictionary having fixed size? = False
If ListDictionary read-only? = False
Is ListDictionary synchronized = False
The ListDictionary has the key 5? = True

Example

Let us see another example −

 Live Demo

using System;
using System.Collections;
using System.Collections.Specialized;
public class Demo {
   public static void Main() {
      ListDictionary dict = new ListDictionary();
      dict.Add("1", "SUV");
      dict.Add("2", "Sedan");
      dict.Add("3", "Utility Vehicle");
      dict.Add("4", "Compact Car");
      dict.Add("5", "SUV");
      dict.Add("6", "Sedan");
      dict.Add("7", "Utility Vehicle");
      dict.Add("8", "Compact Car");
      dict.Add("9", "Crossover");
      dict.Add("10", "Electric Car");
      Console.WriteLine("ListDictionary elements...");
      foreach(DictionaryEntry d in dict) {
         Console.WriteLine(d.Key + " " + d.Value);
      }
      Console.WriteLine("
Is the ListDictionary having fixed size? = "+dict.IsFixedSize);
      Console.WriteLine("If ListDictionary read-only? = "+dict.IsReadOnly);
      Console.WriteLine("Is ListDictionary synchronized = "+dict.IsSynchronized);
      Console.WriteLine("The ListDictionary has the key M? = "+dict.Contains("M"));
   }
}

Output

This will produce the following output −

ListDictionary elements...
1 SUV
2 Sedan
3 Utility Vehicle
4 Compact Car
5 SUV
6 Sedan
7 Utility Vehicle
8 Compact Car
9 Crossover
10 Electric Car
Is the ListDictionary having fixed size? = False
If ListDictionary read-only? = False
Is ListDictionary synchronized = False
The ListDictionary has the key M? = False