ListDictionary Class in C#



The ListDictionary class implements IDictionary using a singly linked list. It is recommended for collections that typically include fewer than 10 items.

Following are the properties of ListDictionary class −

Sr.No Property & Description
1 Count
Gets the number of key/value pairs contained in the ListDictionary.
2 IsFixedSize
Gets a value indicating whether the ListDictionary has a fixed size.
3 IsReadOnly
Gets a value indicating whether the ListDictionary is readonly.
4 IsSynchronized
Gets a value indicating whether the ListDictionary is synchronized (thread safe).
5 Item[Object]
Gets or sets the value associated with the specified.
6 Keys
Gets an ICollection containing the keys in the ListDictionary.
7 SyncRoot
Gets an object that can be used to synchronize access to the ListDictionary.
8 Values
Gets an ICollection containing the values in the ListDictionary.

Following are some of the methods of the ListDictionary class −

Sr.No Methods & Description
1 Add(Object, Object)
Adds an entry with the specified key and value into the ListDictionary.
2 Clear()
Removes all entries from the ListDictionary.
3 Contains(Object)
Determines whether the ListDictionary contains a specific key.
4 CopyTo(Array, Int32)
Copies the ListDictionary entries to a onedimensional Array instance at the specified index.
5 Equals(Object)
Determines whether the specified object is equal to the current object. (Inherited from Object)
6 GetEnumerator()
Returns an IDictionaryEnumerator that iterates through the ListDictionary.
7 GetHashCode()
Serves as the default hash function. (Inherited from Object)
8 GetType()
Gets the Type of the current instance. (Inherited from Object)

Example

Let us now see some examples −

To check if ListDictionary is read-only, the code is as follows −

 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);
      }
      Console.WriteLine("Is the ListDictionary1 having fixed size? = "+dict1.IsFixedSize);
      Console.WriteLine("If ListDictionary1 read-only? = "+dict1.IsReadOnly);
      Console.WriteLine("Is ListDictionary1 synchronized = "+dict1.IsSynchronized);
      Console.WriteLine("The ListDictionary1 has the key M? = "+dict1.Contains("M"));
      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 ListDictionary2 having fixed size? = "+dict2.IsFixedSize);       Console.WriteLine("If ListDictionary2 read-only? = "+dict2.IsReadOnly);       Console.WriteLine("Is ListDictionary2 synchronized = "+dict2.IsSynchronized);       Console.WriteLine("The ListDictionary2 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
Is the ListDictionary1 having fixed size? = False
If ListDictionary1 read-only? = False
Is ListDictionary1 synchronized = False
The ListDictionary1 has the key M? = False
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 ListDictionary2 having fixed size? = False
If ListDictionary2 read-only? = False
Is ListDictionary2 synchronized = False
The ListDictionary2 has the key 5? = True

To check if two ListDictionary objects are equal, 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 elements...");       foreach(DictionaryEntry d in dict2) {          Console.WriteLine(d.Key + " " + d.Value);       }       ListDictionary dict3 = new ListDictionary();       dict3 = dict2;       Console.WriteLine("
Is ListDictionary3 equal to ListDictionary2? = "+(dict3.Equals(dict2)));    } }

Output

This will produce the following output −

ListDictionary1 elements...
A Books
B Electronics
C Smart Wearables
D Pet Supplies
E Clothing
F Footwear
ListDictionary2 elements...
1 One
2 Two
3 Three
4 Four
5 Five
6 Six
Is ListDictionary3 equal to ListDictionary2? = True
Updated on: 2019-12-16T08:11:12+05:30

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