C# | Check if Hashtable is read-only

Last Updated : 11 Jul, 2025
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:
Comment

Explore