C# | Check if Hashtable is read-only Last Updated : 11 Jul, 2025 Comments Improve Suggest changes Like Article Like Report Hashtable.IsReadOnly property is used to get a value indicating whether the Hashtable is read-only or not. Syntax: public virtual bool IsReadOnly { get; } Return Value: This property returns true if the Hashtable is read-only otherwise it returns false. The default is false. Below programs illustrate the above-discussed property: Example 1: CSharp // C# code to check if Hashtable // is read-only or not using System; using System.Collections; class GFG { // Driver code public static void Main() { // Creating a Hashtable Hashtable myTable = new Hashtable(); // Adding elements in Hashtable myTable.Add("G", "Geeks"); myTable.Add("C", "C#"); myTable.Add("D", "Data Structures"); myTable.Add("Q", "Quiz"); // Checking if Hashtable is read-only or not // this will return false Console.WriteLine(myTable.IsReadOnly); } } Output: False Example 2: CSharp // C# code to check if Hashtable // is read-only or not using System; using System.Collections; class GFG { // Driver code public static void Main() { // Creating a Hashtable Hashtable myTable = new Hashtable(); // Adding elements in Hashtable myTable.Add("1", "C"); myTable.Add("2", "C#"); myTable.Add("3", "C++"); myTable.Add("4", "HTML"); myTable.Add("5", "CSS"); // Checking if Hashtable is read-only or not // this will return false Console.WriteLine(myTable.IsReadOnly); } } Output: False Note: A collection that is read-only does not allow the addition, removal, or modification of elements after the collection is created. A collection that is read-only is simply a collection with a wrapper that prevents modifying the collection. Therefore, if changes are made to the underlying collection, the read-only collection reflects those changes. Retrieving the value of this property is an O(1) operation. Reference: https://learn.microsoft.com/en-us/dotnet/api/system.collections.hashtable.isreadonly?view=netframework-4.7.2 Comment More info K Kirti_Mangal Follow Improve Article Tags : C# 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 Data Types in C# 6 min read C# Variables 4 min read C# Literals 5 min read Operators in C# 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 Loops in C# 4 min read C# Jump Statements (Break, Continue, Goto, Return and Throw) 4 min read OOP ConceptsClass and Objects in C# 4 min read Constructors in C# 5 min read C# Inheritance 3 min read Encapsulation in C# 2 min read C# Abstraction 4 min read MethodsMethods in C# 4 min read Method Overloading in C# 4 min read C# | Method Parameters 7 min read Method Overriding in C# 7 min read Anonymous Method in C# 3 min read ArraysArrays in C# 6 min read Jagged Arrays in C# 4 min read Array Class in C# 5 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 StringStrings in C# 6 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