C# StringCollection Class
Last Updated : 04 Feb, 2025
In C#, the StringCollection class is part of the System.Collections.Specialized namespace. It provides a collection of strings that allows us to store and manage a list of strings easily. This class is a type-safe collection that automatically resizes as needed.
- StringCollection class accepts null as a valid value and allows duplicate elements.
- String comparisons are case-sensitive.
- Elements in this collection can be accessed using an integer index.
- Indexes in this collection are zero-based.
Example: This example demonstrates how to add a string to a StringCollection and iterate over the collection to display its elements.
C# // C# code to create a StringCollection using System; using System.Collections; using System.Collections.Specialized; class Geeks { public static void Main() { StringCollection s = new StringCollection(); // Adding elements in StringCollection s.Add("Geeks"); s.Add("for"); s.Add("Geeks"); foreach(Object i in s) { Console.WriteLine(i); } } } Declaration of StringCollection
In C#, the declaration of StringCollection is as follow:
StringCollection collection = new StringCollection();
Constructor
StringCollection(): Initializes a new instance of the StringCollection class.
Example: This example demonstrates the working of StringCollection.
C# // Example of StringCollection using System; using System.Collections; using System.Collections.Specialized; class Geeks { public static void Main() { StringCollection s = new StringCollection(); // Adding elements in StringCollection s.Add("A"); s.Add("B"); s.Add("C"); // Displaying objects foreach(Object i in s) { Console.WriteLine(i); } } } Properties
The StringCollection class provides several properties to access its state.
| Property | Description |
|---|
| Count | Gets the number of strings contained in the StringCollection. |
| IsReadOnly | Gets a value indicating whether the StringCollection is read-only. |
| IsSynchronized | Gets a value indicating whether access to the StringCollection is synchronized (thread safe). |
| Item[Int32] | Gets or sets the element at the specified index. |
| SyncRoot | Gets an object that can be used to synchronize access to the StringCollection. |
Example: This example demonstrates how to use StringColelction class, including the AddRange method to add multiple elements, the IsReadOnly property to check if the collection is ready to read-only and the count property to get the number of elements in the collection.
C# // C# code to demonstrates the StringCollection // Class Properties using System; using System.Collections; using System.Collections.Specialized; class Geeks { public static void Main() { // creating a StringCollection StringCollection s = new StringCollection(); // creating a string array String[] arr = new String[] { "A", "B", "C", "D", "E" }; // Copying the elements of a string // array to the end of the StringCollection s.AddRange(arr); // IsReadOnly Property // checking if StringCollection is // read-only Console.WriteLine(s.IsReadOnly); // Using Count Property // To get number of Strings contained // in the StringCollection Console.WriteLine("Number of strings are: " + s.Count); } } OutputFalse Number of strings are: 5
Methods
| Method | Description |
|---|
| Add(String) | Adds a string to the end of the StringCollection. |
| AddRange(String[]) | Copies the elements of a string array to the end of the StringCollection. |
| Clear() | Removes all the strings from the StringCollection. |
| Contains(String) | Determines whether the specified string is in the StringCollection. |
| CopyTo(String[], Int32) | Copies the entire StringCollection values to a one-dimensional array of strings, starting at the specified index of the target array. |
| Equals(Object) | Determines whether the specified object is equal to the current object. |
| GetEnumerator() | Returns a StringEnumerator that iterates through the StringCollection. |
| GetHashCode() | Serves as the default hash function. |
| GetType() | Gets the Type of the current instance. |
| IndexOf(String) | Searches for the specified string and returns the zero-based index of the first occurrence within the StringCollection. |
| Insert(Int32, String) | Inserts a string into the StringCollection at the specified index. |
| MemberwiseClone() | Creates a shallow copy of the current Object. |
| Remove(String) | Removes the first occurrence of a specific string from the StringCollection. |
| RemoveAt(Int32) | Removes the string at the specified index of the StringCollection. |
| ToString() | Returns a string that represents the current object. |
Example 1: This example demonstrates how to use AddRange and CopyTo method of the StringCollection class to copy elements from a collection to a string array.
C# // C# code to copy StringCollection to array, // starting at the specified index of // the target array using System; using System.Collections; using System.Collections.Specialized; class Geeks { public static void Main() { // creating a StringCollection named s StringCollection s = new StringCollection(); // creating a string array named arr String[] arr = new String[] { "A", "B", "C", "D", "E" }; // Copying the elements of a string // array to the end of the StringCollection s.AddRange(arr); // creating a String array named arr2 String[] arr2 = new String[s.Count]; // Copying StringCollection to array arr2 // starting from index 0 s.CopyTo(arr2, 0); // Displaying elements in array arr2 for (int i = 0; i < arr2.Length; i++) { Console.WriteLine(arr2[i]); } } } Example 2: This example demonstrates how to add elements to a StringCollection using AddRange, display its elements and then remove all elements using the clear() method.
C# // C# code to insert a string into // the StringCollection at the // specified index using System; using System.Collections; using System.Collections.Specialized; class Geeks { public static void Main() { // creating a StringCollection named s StringCollection s = new StringCollection(); // creating a string array named arr String[] arr = new String[] { "A", "B", "C", "D" }; // Copying the elements of a string // array to the end of the StringCollection s.AddRange(arr); Console.WriteLine("Initially elements in StringCollection are: "); // Displaying elements in StringCollection foreach(Object i in s) Console.WriteLine(i); // Removing all the elements from StringCollection s.Clear(); Console.WriteLine("After Removing: "); // Displaying elements in StringCollection foreach(Object i in s) Console.WriteLine(i); } } OutputInitially elements in StringCollection are: A B C D After Removing: