How to get Synchronize access to the StringCollection in C#

StringCollection.SyncRoot Property is used to get an object which can be used to synchronize access to the StringCollection. This class library that represents a collection of strings. StringCollection class is defined in the System.Collections.Specialized namespace.

Syntax: public virtual object SyncRoot { get; }

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

Important Points:

• Synchronization of an object is done so that only one thread can manipulate the data in the StringCollection.
• 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 StringCollection named st, 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 StringCollection 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 StringCollection
        StringCollection st = new StringCollection();

        // Adding elements to StringCollection
        st.Add("C");
        st.Add("C++");
        st.Add("Java");
        st.Add("C#");
        st.Add("HTML");

        // Using the SyncRoot property
        lock(st.SyncRoot)
        {
            foreach(object ob in st)
            {
                Console.WriteLine(ob);
            }
        }
    }
}
}

Output:

C
C++
Java
C#
HTML

Example 2:

// C# program to illustrate the
// use of SyncRoot property of
// the StringCollection 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 StringCollection
        StringCollection st = new StringCollection();

        // Adding elements to StringCollection
        st.Add("Geeks");
        st.Add("Classes");
        st.Add("on");
        st.Add("Data Structure");
        st.Add("Noida");

        // Using the SyncRoot property
        lock(st.SyncRoot)
        {
            foreach(object ob in st)
            {
                Console.WriteLine(ob);
            }
        }
    }
}
}

Output:

Geeks
Classes
on
Data Structure
Noida

Reference:

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