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 illustrate the above-discussed property:

Example 1:

// 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:

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