Defining Dynamic Array

Question

How can I define a dynamic array in C#?

Answer 1

Have a look at

• C# List Examples
• C# List and ArrayList Collections
• List Class

Answer 2

C# doesn't provide dynamic arrays. Instead, it offers List class which works the same way.

To use lists, write at the top of your file:

using System.Collections.Generic;

And where you want to make use of a list, write (example for strings):

List<string> mylist = new List<string>();
mylist.Add("First string in list");

Answer 3

like so

int nSize = 17;
int[] arrn = new int[nSize];

nSize++;
arrn = new int[nSize];

Answer 4

Take a look at Array.Resize if you need to resize an array.

    // Create and initialize a new string array.
    String[] myArr = {"The", "quick", "brown", "fox", "jumps", 
        "over", "the", "lazy", "dog"};

    // Resize the array to a bigger size (five elements larger).
    Array.Resize(ref myArr, myArr.Length + 5);

    // Resize the array to a smaller size (four elements).
    Array.Resize(ref myArr, 4);

Alternatively you could use the List class as others have mentioned. Make sure you specify an initial size if you know it ahead of time to keep the list from having to resize itself underneath. See the remarks section of the initial size link.

    List<string> dinosaurs = new List<string>(4);

    Console.WriteLine("\nCapacity: {0}", dinosaurs.Capacity);

    dinosaurs.Add("Tyrannosaurus");
    dinosaurs.Add("Amargasaurus");
    dinosaurs.Add("Mamenchisaurus");
    dinosaurs.Add("Deinonychus");

If you need the array from the List, you can use the ToArray() function on the list.

    string[] dinos = dinosaurs.ToArray();