C# | Check if an Array has fixed size or not Last Updated : 11 Jul, 2025 Comments Improve Suggest changes Like Article Like Report Array.IsFixedSize Property is used to get a get a value indicating whether the Array has a fixed size. This property implements the IList.IsFixedSize Property . Syntax: public bool IsFixedSize { get; } Property Value: This property is always return true for all arrays. Below programs illustrate the use of above-discussed property: Example 1: CSharp // C# program to illustrate // IsFixedSize of Array class using System; namespace geeksforgeeks { class GFG { // Main Method public static void Main() { // declares an 1D Array of string string[] topic; // allocating memory for topic. topic = new string[] {"Array, ", "String, ", "Stack, ", "Queue, ", "Exception, ", "Operators"}; // Displaying Elements of the array Console.WriteLine("Topic of C#:"); foreach(string ele in topic) Console.WriteLine(ele + " "); Console.WriteLine(); // Here we check whether is // array of fixed size or not Console.WriteLine("Result: " + topic.IsFixedSize); } } } Output: Topic of C#: Array, String, Stack, Queue, Exception, Operators Result: True Example 2: CSharp // C# program to illustrate // IsFixedSize of Array class using System; namespace geeksforgeeks { class GFG { // Main Method public static void Main() { // declares a 1D Array of string // and assigning null to it string[] str = new string[] {null}; // Here we check whether is // array of fixed size or not Console.WriteLine("Result: " + str.IsFixedSize); } } } Output: Result: True Note: Array implements the IsFixedSize property because it is required by the System.Collections.IList interface. An array with a fixed size does not allow the addition or removal of elements after the creation of an array, but modification of existing elements are allowed. Retrieving the value of this property is an O(1) operation. Reference: https://learn.microsoft.com/en-us/dotnet/api/system.array.isfixedsize?view=netframework-4.7.2 Comment More infoAdvertise with us K Kirti_Mangal Follow Improve Article Tags : C# CSharp-Arrays 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