C# | Check if the ArrayList has a fixed size Last Updated : 11 Jul, 2025 Comments Improve Suggest changes Like Article Like Report 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. ArrayList.IsFixedSize property is used to check whether the ArrayList has a fixed size or not. Properties: Elements can be added or removed from the Array List collection at any point in time. The ArrayList is not guaranteed to be sorted. The capacity of an ArrayList is the number of elements the ArrayList can hold. Elements in this collection can be accessed using an integer index. Indexes in this collection are zero-based. It also allows duplicate elements. Using multidimensional arrays as elements in an ArrayList collection is not supported. Syntax: public virtual bool IsFixedSize { get; } Return Value: This method returns True if the ArrayList has a fixed size, otherwise returns False. The default value is False. Below programs illustrate the use of ArrayList.IsFixedSize Property: Example 1: CSHARP // C# code to check if the ArrayList // has fixed size or not using System; using System.Collections; using System.Collections.Generic; class GFG { // Driver code public static void Main() { // Creating an ArrayList ArrayList myList = new ArrayList(); // Adding elements to ArrayList myList.Add("A"); myList.Add("B"); myList.Add("C"); myList.Add("D"); myList.Add("E"); myList.Add("F"); // To check if the ArrayList has fixed size or not Console.WriteLine(myList.IsFixedSize); } } Output: False Example 2: CSharp // C# code to check if the ArrayList // has fixed size or not using System; using System.Collections; using System.Collections.Generic; class GFG { // Driver code public static void Main() { // Creating an ArrayList ArrayList myList = new ArrayList(); // Adding elements to ArrayList myList.Add("1"); myList.Add("2"); myList.Add("3"); myList.Add("4"); myList.Add("5"); myList.Add("6"); // To check if the ArrayList // has fixed size or not // it will return false Console.WriteLine(myList.IsFixedSize); // Create a fixed-size wrapper // around the ArrayList ArrayList myListfixed = ArrayList.FixedSize(myList); // To check if the ArrayList // has fixed size or not // it will return true Console.WriteLine(myListfixed.IsFixedSize); } } Output: False True Note: A collection with a fixed size does not allow the addition or removal of elements after the collection is created, but it allows the modification of existing elements. Retrieving the value of this property is an O(1) operation. Reference: https://learn.microsoft.com/en-us/dotnet/api/system.collections.arraylist.isfixedsize?view=netframework-4.7.2 Comment More infoAdvertise with us S Sahil_Bansall Follow Improve Article Tags : Misc C# CSharp-Collections-Namespace CSharp-Collections-ArrayList Practice Tags : Misc 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