C# | How to get Synchronize access to the ArrayList Last Updated : 11 Jul, 2025 Comments Improve Suggest changes Like Article Like Report ArrayList.SyncRoot Property is used to get an object which can be used to synchronize access to the ArrayList. ArrayList represents an ordered collection of an object that can be indexed individually. It is basically an alternative to an array. It also allows dynamic memory allocation, adding, searching and sorting items in the list. Important Points: Synchronization of an object is done so that only one thread can manipulate the data in the ArrayList. 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. Syntax: public virtual object SyncRoot { get; } Property Value: An object that can be used to synchronize access to the ArrayList. Example 1: In this code, we are using SyncRoot to get Synchronized access to the ArrayList named arrlist, which is not a thread-safe procedure and can cause an exception. So to avoid the exception we lock the collection. csharp // C# program to illustrate the // use of SyncRoot property of // the ArrayList using System; using System.Threading; using System.Collections; namespace sync_root { class GFG { // Main Method static void Main(string[] args) { // Declaring an ArrayList ArrayList arrlist = new ArrayList(); // Adding elements to ArrayList arrlist.Add(1); arrlist.Add(2); arrlist.Add(3); arrlist.Add(4); arrlist.Add(5); // Using the SyncRoot property lock(arrlist.SyncRoot) { // foreach loop to display // the elements in arrlist foreach(Object i in arrlist) Console.WriteLine(i); } } } } Output: 1 2 3 4 5 Example 2: csharp // C# program to illustrate the // use of SyncRoot property of // the ArrayList using System; using System.Threading; using System.Collections; namespace sync_root { class GFG { // Main Method static void Main(string[] args) { // Declaring an ArrayList ArrayList arrlist = new ArrayList(); // Adding elements to ArrayList arrlist.Add("C"); arrlist.Add("C++"); arrlist.Add("Java"); arrlist.Add("C#"); arrlist.Add("HTML"); // Using the SyncRoot property lock(arrlist.SyncRoot) { // foreach loop to display // the elements in arrlist foreach(Object i in arrlist) Console.WriteLine(i); } } } } Output: C C++ Java C# HTML Reference: https://learn.microsoft.com/en-us/dotnet/api/system.collections.arraylist.syncroot?view=netframework-4.7.2 Comment More infoAdvertise with us K Kirti_Mangal Follow Improve Article Tags : C# CSharp-Collections-Namespace CSharp-Collections-ArrayList Explore IntroductionC# Tutorial 4 min read Introduction to .NET Framework 6 min read C# .NET Framework (Basic Architecture and Component Stack) 6 min read C# Hello World 4 min read Common Language Runtime (CLR) in C# 4 min read FundamentalsC# Identifiers 2 min read C# Data Types 7 min read C# Variables 4 min read C# Literals 5 min read C# Operators 7 min read C# Keywords 5 min read Control StatementsC# Decision Making (if, if-else, if-else-if ladder, nested if, switch, nested switch) 5 min read C# Switch Statement 4 min read C# Loops 4 min read C# Jump Statements (Break, Continue, Goto, Return and Throw) 4 min read OOP ConceptsC# Class and Objects 5 min read C# Constructors 5 min read C# Inheritance 6 min read C# Encapsulation 4 min read C# Abstraction 4 min read MethodsC# Methods 4 min read C# Method Overloading 4 min read C# | Method Parameters 7 min read C# Method Overriding 9 min read Anonymous Method in C# 3 min read ArraysC# Arrays 8 min read C# Jagged Arrays 4 min read C# Array Class 7 min read How to Sort an Array in C# | Array.Sort() Method Set - 1 8 min read How to find the rank of an array in C# 2 min read ArrayListArrayList in C# 6 min read C# ArrayList Class 7 min read C# | Array vs ArrayList 2 min read StringC# Strings 7 min read C# Verbatim String Literal - @ 5 min read C# String Class 9 min read C# StringBuilder 4 min read C# String vs StringBuilder 3 min read TupleC# Tuple 7 min read C# Tuple Class 3 min read C# ValueTuple 7 min read C# ValueTuple Struct 4 min read IndexersC# Indexers 4 min read C# Multidimensional Indexers 5 min read C# - Overloading of Indexers 3 min read Like