Skip to content

Courses
Tutorials
Practice
Contests

C# Data Types
C# Decision Making
C# Methods
C# Delegates
C# Constructors
C# Arrays
C# ArrayList
C# String
C# Tuple
C# Indexers
C# Interface
C# Multithreading
C# Exception

C# | Check if the ArrayList is read-only

C# | Check if an array is read-only or not

Last Updated : 01 Feb, 2019

Comments

Improve

Suggest changes

Like Article

Like

Report

Array.IsReadOnly Property is used to get a value that indicates whether the Array is read-only or not.

Syntax:

public bool IsReadOnly { get; }

Property Value: This property always returns false for all arrays.

Below programs illustrate the use of above-discussed property:

Example 1:

   // C# program to illustrate 
// IsReadOnly Property of 
// Array class 
using System; 
namespace geeksforgeeks { 
  
class GFG { 
  
    // Main Method 
    public static void Main() 
    { 
  
        // declares an 1D Array of string 
        string[] topic; 
  
        // assigning null to array 
        topic = new string[] { null }; 
  
        // Here we check whether is 
        // array of fixed size or not 
        Console.WriteLine("Result: " + topic.IsReadOnly); 
    } 
} 
} 
 
  

Output:

  Result: False

Example 2:

   // C# program to illustrate 
// IsReadOnly Property of 
// Array class 
using System; 
namespace geeksforgeeks { 
  
class GFG { 
  
    // Main Method 
    public static void Main() 
    { 
  
        // Two-dimensional array  
        int[, ] arr = new int[, ] {{1, 2},  
                                   {3, 4},   
                                   {5, 6},   
                                   {7, 8}};  
  
  
        // Here we check whether is 
        // array of fixed size or not 
        Console.WriteLine("Result: " + arr.IsReadOnly); 
    } 
} 
} 
 
  

Output:

  Result: False

Note:

Array implements the IsReadOnly property because it is needed by the System.Collections.IList interface.
An array which is read-only does not allow the addition, removal, or modification of elements after the creation of an array.
If a user requires a read-only collection, then he or she must use a System.Collections class which implements the System.Collections.IList interface.
If a user cast or convert an array to an IList interface object, the IList.IsReadOnly property returns false. However, if the user cast or convert an array to an IList<T> interface, the IsReadOnly property returns true.
Retrieving the value of this property is an O(1) operation.

Reference:

https://docs.microsoft.com/en-us/dotnet/api/system.array.isreadonly?view=netframework-4.7.2

C# | Check if the ArrayList is read-only

K

Kirti_Mangal

Improve

Article Tags :

C#
CSharp-Arrays

Similar Reads

C# | Check if the BitArray is read-only

The BitArray class manages a compact array of bit values, which are represented as Booleans, where true indicates that the bit is on i.e, 1 and false indicates the bit is off i.e, 0. This class is contained in System.Collections namespace. BitArray.IsReadOnly property is used to get a value indicati

C# | Check if the ArrayList is read-only

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.IsReadOnly property is used to check whether the ArrayList is rea

C# | Check if an Array has fixed size or not

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

C# | Check if a SortedList is read-only

SortedList class is a collection of (key, value) pairs which are sorted according to keys. Those pairs can be accessible by key and as well as by index(zero-based indexing). This comes under System.Collections namespace. SortedList.IsReadOnly property is used to get a value which indicates that a So

C# | Check if ListDictionary is read-only

ListDictionary.IsReadOnly property is used to get a value indicating whether the ListDictionary is read-only or not. Syntax: public bool IsReadOnly { get; } Return Value : This property always returns false. Example: // C# code to check if ListDictionary is read-only using System; using System.Colle

C# | Check if Hashtable is read-only

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 illustrat

C# | Check if HybridDictionary is read only

HybridDictionary.IsReadOnly property is used to get a value that indicates whether the HybridDictionary is read-only or not. Syntax: public bool IsReadOnly { get; } Return Value: This property always returns false. Below programs illustrate the use of HybridDictionary.IsReadOnly property: Example 1:

C# | Creating a read-only wrapper for the ArrayList

ArrayList.ReadOnly(ArrayList) Method is used to get a read-only ArrayList wrapper. Syntax: public static System.Collections.ArrayList ReadOnly(System.Collections.ArrayList list); Here, the list is the ArrayList which is to be wrapped. Return Value: It returns a read-only ArrayList Wrapper around the

C# | Check if OrderedDictionary collection is read-only

OrderedDictionary.IsReadOnly property is used to get a value that indicates whether the OrderedDictionary collection is read-only or not. Syntax : public bool IsReadOnly { get; } Return Value: This property returns True if the OrderedDictionary collection is read-only, otherwise, False. The default

C# | Check if the StringCollection is read-only

StringCollection class is a new addition to the .NET Framework class library that represents a collection of strings. StringCollection class is defined in the System.Collections.Specialized namespace. StringCollection.IsReadOnly property is used to get a value indicating whether the StringCollection

Corporate & Communications Address:

A-143, 7th Floor, Sovereign Corporate Tower, Sector- 136, Noida, Uttar Pradesh (201305)

Registered Address:

K 061, Tower K, Gulshan Vivante Apartment, Sector 137, Noida, Gautam Buddh Nagar, Uttar Pradesh, 201305

Advertise with us

Company
About Us
Legal
Privacy Policy
In Media
Contact Us
Advertise with us
GFG Corporate Solution
Placement Training Program

Languages
Python
Java
C++
PHP
GoLang
SQL
R Language
Android Tutorial
Tutorials Archive

DSA
Data Structures
Algorithms
DSA for Beginners
Basic DSA Problems
DSA Roadmap
Top 100 DSA Interview Problems
DSA Roadmap by Sandeep Jain
All Cheat Sheets

Data Science & ML
Data Science With Python
Data Science For Beginner
Machine Learning
ML Maths
Data Visualisation
Pandas
NumPy
NLP
Deep Learning

Web Technologies
HTML
CSS
JavaScript
TypeScript
ReactJS
NextJS
Bootstrap
Web Design

Python Tutorial
Python Programming Examples
Python Projects
Python Tkinter
Python Web Scraping
OpenCV Tutorial
Python Interview Question
Django

Computer Science
Operating Systems
Computer Network
Database Management System
Software Engineering
Digital Logic Design
Engineering Maths
Software Development
Software Testing

DevOps
Git
Linux
AWS
Docker
Kubernetes
Azure
GCP
DevOps Roadmap

System Design
High Level Design
Low Level Design
UML Diagrams
Interview Guide
Design Patterns
OOAD
System Design Bootcamp
Interview Questions

Inteview Preparation
Competitive Programming
Top DS or Algo for CP
Company-Wise Recruitment Process
Company-Wise Preparation
Aptitude Preparation
Puzzles

School Subjects
Mathematics
Physics
Chemistry
Biology
Social Science
English Grammar
Commerce
World GK

GeeksforGeeks Videos
DSA
Python
Java
C++
Web Development
Data Science
CS Subjects

@GeeksforGeeks, Sanchhaya Education Private Limited, All rights reserved

We use cookies to ensure you have the best browsing experience on our website. By using our site, you acknowledge that you have read and understood our Cookie Policy & Privacy Policy

Improvement

Suggest Changes

Help us improve. Share your suggestions to enhance the article. Contribute your expertise and make a difference in the GeeksforGeeks portal.

geeksforgeeks-suggest-icon

Create Improvement

Enhance the article with your expertise. Contribute to the GeeksforGeeks community and help create better learning resources for all.

geeksforgeeks-improvement-icon

Suggest Changes

min 4 words, max Words Limit:1000

Thank You!

Your suggestions are valuable to us.

What kind of Experience do you want to share?

Interview Experiences

Admission Experiences

Career Journeys

Work Experiences

Campus Experiences

Competitive Exam Experiences