C# | Creating a synchronized (thread-safe) wrapper for the Hashtable Last Updated : 11 Jul, 2025 Comments Improve Suggest changes Like Article Like Report Hashtable.Synchronized(Hashtable) Method is used to return a synchronized (thread-safe) wrapper for the Hashtable.Syntax: public static System.Collections.Hashtable Synchronized (System.Collections.Hashtable table); Here table is the Hashtable which is to be synchronized.Return Value: This method returns a synchronized (thread-safe) wrapper for the Hashtable.Exception: This method will throw the ArgumentNullException if the table is null. Below programs illustrate the use of above-discussed method:Example 1: CSharp // C# code to get a synchronized (thread- // safe) wrapper for the Hashtable using System; using System.Collections; class GFG { // Main method static void Main(string[] args) { // create and initialize Hash table // using Add() method Hashtable has1 = new Hashtable(); has1.Add("1", "Welcome"); has1.Add("2", "to"); has1.Add("3", "geeks"); has1.Add("4", "for"); has1.Add("5", "geeks"); // Creating a synchronized packing // around the Hashtable Hashtable has2 = Hashtable.Synchronized(has1); // --------- Using IsSynchronized Property // print the status of both Hashtables Console.WriteLine("has1 Hashtable is {0}.", has1.IsSynchronized ? "synchronized" : "not synchronized"); Console.WriteLine("has2 Hashtable is {0}.", has2.IsSynchronized ? "synchronized" : "not synchronized"); } } Output: has1 Hashtable is not synchronized. has2 Hashtable is synchronized. Example 2: CSharp // C# code to get a synchronized (thread- // safe) wrapper for the Hashtable using System; using System.Collections; class GFG { // Main method static void Main(string[] args) { // create and initialize Hash table // there will be no elements Hashtable has1 = new Hashtable(); // it will give runtime error as // table parameter can't be null Hashtable has2 = Hashtable.Synchronized(null); } } Runtime Error: Unhandled Exception: System.ArgumentNullException: Value cannot be null. Parameter name: table Note: This method is a thread-safe for multiple readers and writers. Furthermore, the synchronized wrapper ensures that there is only one writer writing at a time.Enumerating through a collection is intrinsically not a thread-safe process. Other threads can still modify the collection, which causes the enumerator to throw an exception even when a collection is synchronized.To guarantee thread safety during enumeration, you can either lock the collection during the entire enumeration or catch the exceptions resulting from changes made by other threads.This method is an O(1) operation. Reference: https://learn.microsoft.com/en-us/dotnet/api/system.collections.hashtable.synchronized?view=netframework-4.7.2 Comment More infoAdvertise with us K Kirti_Mangal Follow Improve Article Tags : C# CSharp-method CSharp-Collections-Hashtable CSharp-Collections-Namespace 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 2 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