HybridDictionary attempts to optimize Hashtable. 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.
Properties of HybridDictionary Class:
- 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.
Constructors
| Constructor | Description |
|---|---|
| HybridDictionary() | Creates an empty case-sensitive HybridDictionary. |
| HybridDictionary(Boolean) | Creates an empty HybridDictionary with the specified case sensitivity. |
| HybridDictionary(Int32) | Creates a case-sensitive HybridDictionary with the specified initial size. |
| HybridDictionary(Int32, Boolean) | Creates a HybridDictionary with the specified initial size and case sensitivity. |
Example:
// C# code to create a HybridDictionary // with the specified initial size // and case sensitivity. using System;
using System.Collections;
using System.Collections.Specialized;
class GFG {
// Driver code
public static void Main()
{
// Creating a HybridDictionary with the
// specified initial size and case sensitivity.
HybridDictionary myDict = new HybridDictionary(10, false);
// Adding key/value pairs in myDict
myDict.Add("I", "first");
// This will not raise exception as the
// Collection is not case-insensitive
myDict.Add("i", "first");
myDict.Add("II", "second");
myDict.Add("III", "third");
myDict.Add("IV", "fourth");
myDict.Add("V", "fifth");
// Displaying the key/value pairs in myDict
foreach(DictionaryEntry de in myDict)
Console.WriteLine(de.Key + " " + de.Value);
}
} |
Output:
III third V fifth II second i first I first IV fourth
Properties
| 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:
// C# code to get the number of key/value // pairs contained in the HybridDictionary. using System;
using System.Collections;
using System.Collections.Specialized;
class GFG {
// Driver code
public static void Main()
{
// Creating a HybridDictionary named myDict
HybridDictionary myDict = new HybridDictionary();
// Adding key/value pairs in myDict
myDict.Add("Australia", "Canberra");
myDict.Add("Belgium", "Brussels");
myDict.Add("Netherlands", "Amsterdam");
myDict.Add("China", "Beijing");
myDict.Add("Russia", "Moscow");
myDict.Add("India", "New Delhi");
// To get count of key/value pairs in myDict
Console.WriteLine("Total key/value pairs in myDict are : " + myDict.Count);
}
} |
Output:
Total key/value pairs in myDict are : 6
Example 2:
// C# code to check whether the // HybridDictionary is read-only. using System;
using System.Collections;
using System.Collections.Specialized;
class GFG {
// Driver code
public static void Main()
{
// Creating a HybridDictionary named myDict
HybridDictionary myDict = new HybridDictionary();
// Adding key/value pairs in myDict
myDict.Add("A", "Apple");
myDict.Add("B", "Banana");
myDict.Add("C", "Cat");
myDict.Add("D", "Dog");
myDict.Add("E", "Elephant");
myDict.Add("F", "Fish");
// To check whether the HybridDictionary
// is read-only.
Console.WriteLine(myDict.IsReadOnly);
}
} |
Output:
False
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:
// 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 GFG {
// Driver code
public static void Main()
{
// Creating a HybridDictionary named myDict
HybridDictionary myDict = new HybridDictionary();
// Adding key/value pairs in myDict
myDict.Add("A", "Apple");
myDict.Add("B", "Banana");
myDict.Add("C", "Cat");
myDict.Add("D", "Dog");
myDict.Add("E", "Elephant");
myDict.Add("F", "Fish");
// Creating a one-dimensional Array named myArr
DictionaryEntry[] myArr = new DictionaryEntry[myDict.Count];
// copying the HybridDictionary entries
// to a one-dimensional Array instance
// at the specified index
myDict.CopyTo(myArr, 0);
for (int i = 0; i < myArr.Length; i++)
Console.WriteLine(myArr[i].Key + " --> " + myArr[i].Value);
}
} |
Output:
A --> Apple B --> Banana C --> Cat D --> Dog E --> Elephant F --> Fish
Example 2:
// C# code to remove the entry // with the specified key from // the HybridDictionary. using System;
using System.Collections;
using System.Collections.Specialized;
class GFG {
// Driver code
public static void Main()
{
// Creating a HybridDictionary named myDict
HybridDictionary myDict = new HybridDictionary();
// Adding key/value pairs in myDict
myDict.Add("A", "Apple");
myDict.Add("B", "Banana");
myDict.Add("C", "Cat");
myDict.Add("D", "Dog");
myDict.Add("E", "Elephant");
myDict.Add("F", "Fish");
// Displaying the number of key/value
// pairs in HybridDictionary myDict
Console.WriteLine("Number of key/value pairs in myDict are : " + myDict.Count);
// Removing the entry with the
// specified key from the HybridDictionary.
myDict.Remove("C");
// Displaying the number of key/value
// pairs in HybridDictionary myDict
Console.WriteLine("Number of key/value pairs in myDict are : " + myDict.Count);
}
} |
Output:
Number of key/value pairs in myDict are : 6 Number of key/value pairs in myDict are : 5
Reference: