RetroSearch Browse

Home - News ( United States | United Kingdom | Italy | Germany ) - Football scores

Showing content from https://www.geeksforgeeks.org/c-sharp/c-sharp-get-a-collection-of-keys-in-the-stringdictionary/ below:

C# | Get a collection of keys in the StringDictionary

Last Updated : 11 Jul, 2025

StringDictionary.Keys

property is used to get a collection of keys in the StringDictionary.

Syntax:

public virtual System.Collections.ICollection Keys { get; }

Return Value:

ICollection

that provides the keys in the StringDictionary. Below given are some examples to understand the implementation in a better way:

Example 1: CSHARP


 // C# code to get a collection
// of keys in 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");

        // To copy the StringDictionary values to
        // a one-dimensional Array instance at
        // the specified index.
        String[] myKeys = new String[myDict.Count];
        myDict.Keys.CopyTo(myKeys, 0);

        // Getting a collection of keys
        // in the StringDictionary
        for (int i = 0; i < myDict.Count; i++) {
            Console.WriteLine(myKeys[i] + " " + myDict[myKeys[i]]);
        }
    }
}

Output:

d Dog
b Banana
c Cat
a Apple

Example 2: CSHARP


 // C# code to get a collection
// of keys in 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("3", "prime & odd");
        myDict.Add("2", "prime & even");
        myDict.Add("4", "non-prime & even");
        myDict.Add("9", "non-prime & odd");

        // To copy the StringDictionary values to
        // a one-dimensional Array instance at
        // the specified index.
        String[] myKeys = new String[myDict.Count];
        myDict.Keys.CopyTo(myKeys, 0);

        // Getting a collection of keys
        // in the StringDictionary
        for (int i = 0; i < myDict.Count; i++) {
            Console.WriteLine(myKeys[i] + " " + myDict[myKeys[i]]);
        }
    }
}

Output:

2 prime & even
3 prime & odd
9 non-prime & odd
4 non-prime & even

Note:

The order of the keys in the ICollection is unspecified, but it is the same order as the associated values in the ICollection returned by the Values method.
The returned ICollection is not a static copy. Instead, the ICollection refers back to the keys in the original StringDictionary. Therefore, changes to the StringDictionary continue to be reflected in the ICollection.
Retrieving the value of this property is an O(1) operation.

Reference:

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

RetroSearch is an open source project built by @garambo | Open a GitHub Issue

Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo

HTML: 3.2 | Encoding: UTF-8 | Version: 0.7.4