Csharp/CSharp Tutorial/Data Structure/ArrayList ToArray

Convert an ArrayList into an array

<source lang="csharp">using System; using System.Collections;

class MainClass {

 public static void Main() { 
   ArrayList al = new ArrayList(); 
    
   // Add elements to the array list. 
   al.Add(1); 
   al.Add(2); 
   al.Add(3); 
   al.Add(4); 

   Console.Write("Contents: "); 
   foreach(int i in al) 
     Console.Write(i + " "); 
   Console.WriteLine(); 

   // Get the array. 
   int[] ia = (int[]) al.ToArray(typeof(int)); 
   int sum = 0; 

   // sum the array 
   for(int i=0; i<ia.Length; i++) 
     sum += ia[i]; 

   Console.WriteLine("Sum is: " + sum); 
 } 

}</source>

Contents: 1 2 3 4
Sum is: 10

Convert user-defined objects in an ArrayList to an array

<source lang="csharp">using System; using System.Collections; using System.Collections.Specialized; class MyClass{

  public string MyName="";   

} class MainClass {

 static void Main(string[] args)
 {
   ArrayList classList = new ArrayList();
   classList.AddRange(new MyClass[] { new MyClass(), 
                                          new MyClass(), 
                                          new MyClass()});
   Console.WriteLine("Items in List: {0}", classList.Count);
      // Get object array from ArrayList & print again.
   object[] arrayOfMyClasss = classList.ToArray();
   for(int i = 0; i < arrayOfMyClasss.Length; i++)
   {
     Console.WriteLine("MyClass name: {0}", 
       ((MyClass)arrayOfMyClasss[i]).MyName);
   }
 }

}</source>

Items in List: 3
MyClass name:
MyClass name:
MyClass name:

Use ArrayList.ToArray to create a strongly typed string array from the contents of the collection

<source lang="csharp">using System; using System.Collections; class MainClass {

   public static void Main(string[] args)
   {
       // Create a new ArrayList and populate it.
       ArrayList list = new ArrayList(5);
       list.Add("B");
       list.Add("G");
       list.Add("J");
       list.Add("S");
       list.Add("M");
       string[] array3 = (string[])list.ToArray(typeof(String));
       Console.WriteLine("Array 3:");
       foreach (string s in array3) 
       {
           Console.WriteLine("\t{0}", s);
       }
   }

}</source>

Array 3:
        B
        G
        J
        S
        M