StringCollection Class in C#

The StringCollection class in C# is a specialized collection that stores strings. It is part of the System.Collections.Specialized namespace and provides methods specifically designed for string operations, making it more efficient than generic collections when working exclusively with strings.

Properties

Following are the key properties of the StringCollection class −

Methods

Following are the commonly used methods of the StringCollection class −

Using Add() and Contains() Methods

The following example demonstrates adding strings to a StringCollection and checking if a specific string exists −

using System;
using System.Collections.Specialized;

public class Demo {
    public static void Main() {
        StringCollection stringCol = new StringCollection();
        String[] arr = new String[] { "100", "200", "300", "400", "500" };
        
        Console.WriteLine("Array elements...");
        foreach (string res in arr) {
            Console.WriteLine(res);
        }
        
        stringCol.AddRange(arr);
        Console.WriteLine("Count: " + stringCol.Count);
        Console.WriteLine("Does the collection contain '300'? " + stringCol.Contains("300"));
        Console.WriteLine("Does the collection contain '800'? " + stringCol.Contains("800"));
    }
}

The output of the above code is −

Array elements...
100
200
300
400
500
Count: 5
Does the collection contain '300'? True
Does the collection contain '800'? False

Using Remove() and Clear() Methods

The following example shows how to remove specific items and clear the entire collection −

using System;
using System.Collections.Specialized;

public class Demo {
    public static void Main() {
        StringCollection strCol = new StringCollection();
        strCol.Add("Apple");
        strCol.Add("Banana");
        strCol.Add("Cherry");
        strCol.Add("Date");
        
        Console.WriteLine("Original collection:");
        foreach (string fruit in strCol) {
            Console.WriteLine(fruit);
        }
        
        strCol.Remove("Banana");
        Console.WriteLine("\nAfter removing 'Banana':");
        foreach (string fruit in strCol) {
            Console.WriteLine(fruit);
        }
        
        Console.WriteLine("Count: " + strCol.Count);
        
        strCol.Clear();
        Console.WriteLine("Count after Clear(): " + strCol.Count);
    }
}

The output of the above code is −

Original collection:
Apple
Banana
Cherry
Date

After removing 'Banana':
Apple
Cherry
Date
Count: 3
Count after Clear(): 0

Using Index-Based Access

StringCollection supports index-based access to elements using the Item[Int32] property −

using System;
using System.Collections.Specialized;

public class Demo {
    public static void Main() {
        StringCollection colors = new StringCollection();
        colors.Add("Red");
        colors.Add("Green");
        colors.Add("Blue");
        
        Console.WriteLine("Accessing elements by index:");
        for (int i = 0; i < colors.Count; i++) {
            Console.WriteLine("Index " + i + ": " + colors[i]);
        }
        
        colors[1] = "Yellow";
        Console.WriteLine("\nAfter modifying index 1:");
        foreach (string color in colors) {
            Console.WriteLine(color);
        }
    }
}

The output of the above code is −

Accessing elements by index:
Index 0: Red
Index 1: Green
Index 2: Blue

After modifying index 1:
Red
Yellow
Blue

Conclusion

The StringCollection class provides a specialized, efficient way to work with collections of strings in C#. It offers useful methods like Add(), Remove(), Contains(), and AddRange(), along with index-based access. While modern development often uses generic collections like List<string>, StringCollection remains useful for scenarios requiring specialized string collection functionality.