Add Method

Collection<T>.Add Method

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

Adds an object to the end of the Collection<T>.

Namespace:  System.Collections.ObjectModel
Assembly:  mscorlib (in mscorlib.dll)

public void Add(
	T item
)

Parameters

item
Type: T
The object to be added to the end of the Collection<T>. The value can be null for reference types.

Implements

ICollection<T>.Add(T)

Collection<T> accepts null as a valid value for reference types and allows duplicate elements.

This method is an O(1) operation.

The following code example demonstrates many of the properties and methods of Collection<T>. The code example creates a collection of strings, uses the Add method to add several strings, displays the Count, and lists the strings. The example uses the IndexOf method to find the index of a string and the Contains method to determine whether a string is in the collection. The example inserts a string using the Insert method and retrieves and sets strings using the default Item property (the indexer in C#). The example removes strings by string identity using the Remove method and by index using the RemoveAt method. Finally, the Clear method is used to clear all strings from the collection.


using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;

public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      Collection<string> dinosaurs = new Collection<string>();

      dinosaurs.Add("Psitticosaurus");
      dinosaurs.Add("Caudipteryx");
      dinosaurs.Add("Compsognathus");
      dinosaurs.Add("Muttaburrasaurus");

      outputBlock.Text += String.Format("{0} dinosaurs:", dinosaurs.Count) + "\n";
      Display(outputBlock, dinosaurs);

      outputBlock.Text += String.Format("\nIndexOf(\"Muttaburrasaurus\"): {0}",
          dinosaurs.IndexOf("Muttaburrasaurus")) + "\n";

      outputBlock.Text += String.Format("\nContains(\"Caudipteryx\"): {0}",
          dinosaurs.Contains("Caudipteryx")) + "\n";

      outputBlock.Text += String.Format("\nInsert(2, \"Nanotyrannus\")") + "\n";
      dinosaurs.Insert(2, "Nanotyrannus");
      Display(outputBlock, dinosaurs);

      outputBlock.Text += String.Format("\ndinosaurs[2]: {0}", dinosaurs[2]) + "\n";

      outputBlock.Text += "\ndinosaurs[2] = \"Microraptor\"" + "\n";
      dinosaurs[2] = "Microraptor";
      Display(outputBlock, dinosaurs);

      outputBlock.Text += "\nRemove(\"Microraptor\")" + "\n";
      dinosaurs.Remove("Microraptor");
      Display(outputBlock, dinosaurs);

      outputBlock.Text += "\nRemoveAt(0)" + "\n";
      dinosaurs.RemoveAt(0);
      Display(outputBlock, dinosaurs);

      outputBlock.Text += "\ndinosaurs.Clear()" + "\n";
      dinosaurs.Clear();
      outputBlock.Text += String.Format("Count: {0}", dinosaurs.Count) + "\n";
   }

   private static void Display(System.Windows.Controls.TextBlock outputBlock, Collection<string> cs)
   {
      outputBlock.Text += "\n";
      foreach (string item in cs)
      {
         outputBlock.Text += item + "\n";
      }
   }
}

/* This code example produces the following output:

4 dinosaurs:

Psitticosaurus
Caudipteryx
Compsognathus
Muttaburrasaurus

IndexOf("Muttaburrasaurus"): 3

Contains("Caudipteryx"): True

Insert(2, "Nanotyrannus")

Psitticosaurus
Caudipteryx
Nanotyrannus
Compsognathus
Muttaburrasaurus

dinosaurs[2]: Nanotyrannus

dinosaurs[2] = "Microraptor"

Psitticosaurus
Caudipteryx
Microraptor
Compsognathus
Muttaburrasaurus

Remove("Microraptor")

Psitticosaurus
Caudipteryx
Compsognathus
Muttaburrasaurus

RemoveAt(0)

Caudipteryx
Compsognathus
Muttaburrasaurus

dinosaurs.Clear()
Count: 0
 */


Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

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