How to get Synchronize access to the HybridDictionary in C#

HybridDictionary.SyncRoot Property is used to get an object which can be used to synchronize access to the HybridDictionary. 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.

Syntax: public virtual object SyncRoot { get; }

Property Value: An object which can be used to synchronize access to the HybridDictionary.

Important Points:

• Synchronization of an object is done so that only one thread can manipulate the data in the HybridDictionary.
• A property is a member of a class that provides a means for reading, writing and computing private data fields.
• The synchronizing code cannot directly perform on the collection, so it must perform operations on the SyncRoot of the collection in order to guarantee the proper operation of collections that are derived from other objects.
• Retrieving the value of this property is an O(1) operation.

Below programs illustrate the use of the above-discussed property:

Example 1: In this code, we are using SyncRoot to get Synchronized access to the HybridDictionary named hd, which is not a thread-safe procedure and can cause an exception. So to avoid the exception we lock the collection during the enumeration.

// C# program to illustrate the
// use of SyncRoot property of
// the HybridDictionary class
using System;
using System.Threading;
using System.Collections;
using System.Collections.Specialized;

namespace sync_root {

class GFG {

    // Main Method
    static void Main(string[] args)
    {

        // Declaring an HybridDictionary
        HybridDictionary hd = new HybridDictionary();

        // Adding elements to HybridDictionary
        hd.Add("1", "HTML");
        hd.Add("2", "CSS");
        hd.Add("3", "PHP");
        hd.Add("4", "JQuery");
        hd.Add("5", "JavaScript");

        // Using the SyncRoot property
        lock(hd.SyncRoot)
        {
            // foreach loop to display
            // the elements in hd
            foreach(DictionaryEntry i in hd)
                Console.WriteLine(i.Key + " ---- " + i.Value);
        }
    }
}
}

Output:

1 ---- HTML
2 ---- CSS
3 ---- PHP
4 ---- JQuery
5 ---- JavaScript

Example 2:

// C# program to illustrate the
// use of SyncRoot property of
// the HybridDictionary class
using System;
using System.Threading;
using System.Collections;
using System.Collections.Specialized;

namespace sync_root {

class GFG {

    // Main Method
    static void Main(string[] args)
    {

        // Declaring an HybridDictionary
        HybridDictionary hd= new HybridDictionary();

        // Adding elements to HybridDictionary
        hd.Add("10", "Shyam");
        hd.Add("20", "Ram");
        hd.Add("30", "Rohit");
        hd.Add("40", "Sohan");
        hd.Add("50", "Rohan");

        // Using the SyncRoot property
        lock(hd.SyncRoot)
        {
            // foreach loop to display
            // the elements in hd
            foreach(DictionaryEntry i in hd)
                Console.WriteLine(i.Key + " ----> " + i.Value);
        }
    }
}
}

Output:

10 ----> Shyam
20 ----> Ram
30 ----> Rohit
40 ----> Sohan
50 ----> Rohan

Reference:

• https://docs.microsoft.com/en-us/dotnet/api/system.collections.specialized.hybriddictionary.syncroot?view=netframework-4.7.2