C# HybridDictionary Class
Last Updated :
04 Feb, 2025
In C#, the HybridDictionary Class is the part of the System.Collections.Specialized namespace. It is a collection that combines the features of both a Hashtable and a ListDictionary. It implements a linked list and hash table data structure. It implements IDictionary by using a ListDictionary when the collection is small, and a Hashtable when the collection is large.
- This class is recommended for cases where the number of elements in a dictionary is unknown.
- It takes advantage of the improved performance of a ListDictionary with small collections, and offers the flexibility of switching to a Hashtable which handles larger collections better than ListDictionary.
- If the initial size of the collection is greater than the optimal size for a ListDictionary, the collection is stored in a Hashtable to avoid the overhead of copying elements from the ListDictionary to a Hashtable.
- A key cannot be null, but a value can.
Example: This example demonstrates how to create a HybridDictrionary class, add key-value pairs, and iterate through it to print each key-value pair.
C#
// C# program to demonstrates the
// working of HybridDictionary class
using System;
using System.Collections;
using System.Collections.Specialized;
class Geeks {
static void Main()
{
// Create a HybridDictionary
HybridDictionary hd = new HybridDictionary();
// Add key-value pairs
hd.Add("1", "Geek1");
hd.Add("2", "Geek2");
hd.Add("3", "Geek3");
hd.Add("4", "Geek4");
// Iterate through the HybridDictionary and print
// each key-value pair
foreach(DictionaryEntry i in hd)
{
Console.WriteLine($"{i.Key}: {i.Value}");
}
}
}
Output1: Geek1
2: Geek2
3: Geek3
4: Geek4
Declaration of HybridDictionary
In C#, the Hybriddictionary is declared as:
HybridDictionary dictionary = new HybridDictionary();
Constructors
Example: This example demonstrates the use of HybridDictionary class with specified initial size and case-senstivity.
C#
// HybridDictioanry with specific initial
// size and case sensitivity
using System;
using System.Collections;
using System.Collections.Specialized;
class Geeks {
public static void Main()
{
// Creating a HybridDictionary with the
// specified initial size and case sensitivity.
HybridDictionary hd= new HybridDictionary(10, false);
// Adding key/value pairs
hd.Add("I", "first");
// This will not raise exception as the
// Collection is not case-insensitive
hd.Add("i", "first");
hd.Add("II", "second");
hd.Add("III", "third");
hd.Add("IV", "fourth");
hd.Add("V", "fifth");
// Displaying the key/value pairs
foreach(DictionaryEntry i in hd)
Console.WriteLine(i.Key + " " + i.Value);
}
}
Outputi first
III third
V fifth
IV fourth
I first
II second
Properties
The HybridDictionary provides several properties to access its state.
| Property | Description |
|---|
| Count | Gets the number of key/value pairs contained in the HybridDictionary. |
| IsFixedSize | Gets a value indicating whether the HybridDictionary has a fixed size. |
| IsReadOnly | Gets a value indicating whether the HybridDictionary is read-only. |
| IsSynchronized | Gets a value indicating whether the HybridDictionary is synchronized (thread safe). |
| Item[Object] | Gets or sets the value associated with the specified key. |
| Keys | Gets an ICollection containing the keys in the HybridDictionary. |
| SyncRoot | Gets an object that can be used to synchronize access to the HybridDictionary. |
| Values | Gets an ICollection containing the values in the HybridDictionary. |
Example 1: This example demonstrates how to get the count of key-value pairs in the dictionary.
C#
// C# program to demonstrates the Count property
using System;
using System.Collections;
using System.Collections.Specialized;
class Geeks {
public static void Main()
{
// Creating a HybridDictionary
HybridDictionary hd = new HybridDictionary();
// Adding key/value pairs
hd.Add(1, 100);
hd.Add(2, 200);
hd.Add(3, 300);
hd.Add(4, 400);
// To get count of key/value pairs
Console.WriteLine("Total key-value pairs are : "
+ hd.Count);
}
}
OutputTotal key-value pairs are : 4
Example 2: This example demonstrates how to check if a HybridDictionary is read-only.
C#
// C# program to demonstrates the isReadOnly property
using System;
using System.Collections;
using System.Collections.Specialized;
class Geeks {
public static void Main()
{
// Creating a HybridDictionary
HybridDictionary hd = new HybridDictionary();
// Adding key/value pairs
hd.Add("1", "Geek1");
hd.Add("2", "Geek2");
hd.Add("3", "Geek3");
hd.Add("4", "Geek4");
// To check whether the HybridDictionary
// is read-only
Console.WriteLine(hd.IsReadOnly);
}
}
Methods
| Method | Description |
|---|
| Add(Object, Object) | Adds an entry with the specified key and value into the HybridDictionary. |
| Clear() | Removes all entries from the HybridDictionary. |
| Contains(Object) | Determines whether the HybridDictionary contains a specific key. |
| CopyTo(Array, Int32) | Copies the HybridDictionary entries to a one-dimensional Array instance at the specified index. |
| Equals(Object) | Determines whether the specified object is equal to the current object. |
| GetEnumerator() | Returns an IDictionaryEnumerator that iterates through the HybridDictionary. |
| GetHashCode() | Serves as the default hash function. |
| GetType() | Gets the Type of the current instance. |
| MemberwiseClone() | Creates a shallow copy of the current Object. |
| Remove(Object) | Removes the entry with the specified key from the HybridDictionary. |
| ToString() | Returns a string that represents the current object. |
Example 1: This example demonstrates how to copy the entries of a HybridDictioanry to a one-dimensional DictionaryEntry array using the CopyTo() Method.
C#
// C# code to copy the HybridDictionary
// entries to a one-dimensional Array
// instance at the specified index
using System;
using System.Collections;
using System.Collections.Specialized;
class Geeks {
public static void Main()
{
// Creating a HybridDictionary
HybridDictionary hd = new HybridDictionary();
// Adding key-value pairs
hd.Add(1, 100);
hd.Add(2, 200);
hd.Add(3, 300);
hd.Add(4, 400);
// Creating a one-dimensional Array
DictionaryEntry[] arr = new DictionaryEntry[hd.Count];
// copying the HybridDictionary entries
// to a one-dimensional Array instance
// at the specified index
hd.CopyTo(arr, 0);
for (int i = 0; i < arr.Length; i++)
Console.WriteLine(arr[i].Key + " --> "
+ arr[i].Value);
}
}
Output1 --> 100
2 --> 200
3 --> 300
4 --> 400
Example 2: This example demonstrates how to add, remove and check the count of key-value pairs in a HybridDictioary.
C#
// C# program to remove the entry
// with the specified key from
// the HybridDictionary
using System;
using System.Collections;
using System.Collections.Specialized;
class Geeks {
public static void Main()
{
// Creating a HybridDictionary
HybridDictionary hd = new HybridDictionary();
// Adding key/value pairs
hd.Add(1, 100 );
hd.Add(2, 200);
hd.Add(3, 300);
hd.Add(4, 400);
// Displaying the number of key/value
// pairs in HybridDictionary
Console.WriteLine("Number of key-value pairs are: "
+ hd.Count);
// Removing the entry with the
// specified key from the HybridDictionary
hd.Remove(3);
// Displaying the number of key/value
// pairs in HybridDictionary
Console.WriteLine("Number of key-value pairs are: "
+ hd.Count);
}
}
OutputNumber of key-value pairs are: 4
Number of key-value pairs are: 3
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