C# | Removing all entries from the StringDictionary

StringDictionary.Clear method is used to remove all the entries from the StringDictionary.

Syntax:

public virtual void Clear ();

Exception: This method will give the NotSupportedException if the StringDictionary is read-only.

Example:

// C# code to remove all entries
// from the StringDictionary
using System;
using System.Collections;
using System.Collections.Specialized;

class GFG {

    // Driver code
    public static void Main()
    {

        // Creating a StringDictionary named myDict
        StringDictionary myDict = new StringDictionary();

        // Adding key and value into the StringDictionary
        myDict.Add("A", "Apple");
        myDict.Add("B", "Banana");
        myDict.Add("C", "Cat");
        myDict.Add("D", "Dog");
        myDict.Add("E", "Elephant");
        myDict.Add("F", "Fish");

        // Displaying the keys and values in StringDictionary
        Console.WriteLine("The number of key/value pairs are : " + myDict.Count);

        foreach(DictionaryEntry dic in myDict)
        {
            Console.WriteLine(dic.Key + " " + dic.Value);
        }

        // Removing all entries from the StringDictionary
        myDict.Clear();

        // Displaying the keys and values in StringDictionary
        Console.WriteLine("The number of key/value pairs are : " + myDict.Count);

        foreach(DictionaryEntry dic in myDict)
        {
            Console.WriteLine(dic.Key + " " + dic.Value);
        }
    }
}

Output:

The number of key/value pairs are : 6
b Banana
c Cat
a Apple
f Fish
d Dog
e Elephant
The number of key/value pairs are : 0

Note: This method is an O(n) operation, where n is Count.

Reference:

• https://docs.microsoft.com/en-us/dotnet/api/system.collections.specialized.stringdictionary.clear?view=netframework-4.7.2