ArrayList Overview of C #

ArrayList class is equivalent to an advanced dynamic array . is a Array The upgrade version of the class.

Overview:

ArrayList is located System.Collections under Namespaces

you can delete and add elements on the fly , in a way, in a sense, , He's an advanced version of the array. , but not the same as an array.

compared to arrays , ArrayList class provides the following features:

? ? 1. The length of the array is fixed ( once declared , cannot be changed beyond the bounds of the array ); The length of the ArrayList can be automatically expanded as needed.

? ? 2. ArrayList provides methods for adding, deleting, and inserting elements within a range ; You can only get or set the value of an element one time in an array.

? ? 3. ArrayList provides methods for wrapping and returning a read-only and fixed-size package to a collection ; The array is not provided.

? ? 4. ArrayList can only be one-dimensional form ; the array can be multidimensional.

ArrayList How to declare :

? ? ArrayList provides 3 constructors ,? The corresponding is the 3 method of declaration :

? ? [1]. the default constructor initializes the internal array with the default size (

? ? ? ? public ArrayList ();

? ? ? ? statement:

? ? ? ? ArrayList list = new Arrarlist ();

? ? ? ? Example : ( declares a ArrayList object and Adds ten int Elements of type )

? ? ? ? ArrayList ArrayList = new ArrayList ();

? ? ? ? for (int i = 0; i <; i++)

? ? ? ? {

? ? ? ? ? ? Arraylist.add (i);

? ? ? ? }

? ? [2]. construct with a ICollection object and add the elements of the collection to the ArrayList :

? ? ? ? Public ArrayList (ICollection);

? ? ? ? statement:

? ? ? ? ArrayList ArrayList = new ArrayList (arrayname);? //arrayname: to add to The name of the array in the ArrayList

? ? ? ? Example: ( add a one-dimensional int array to the ArrayList collection )

? ? ? ? int[] array = new int[] {1,2,3,4,5,6,7};

? ? ? ? ArrayList ArrayList = new ArrayList (array);

? ? [3]. Initialize the inner array with the specified size

? ? ? ? public ArrayList (int);

? ? ? ? statement:

? ? ? ? ArrayList ArrayList = new ArrayList (10);

? ? ? ? Example: ( declare a ArrayList collection with a length of ten and add elements dynamically )

? ? ? ? ArrayList ArrayList = new ArrayList (10);

? ? ? ? for (int i = 0; i < Arraylist.count; i++)

? ? ? ? {

? ? ? ? ? ? ?//arraylist.count : Gets the length of the ArrayList object

? ? ? ? ? ? Arraylist.add (i);

? ? ? ? }

ArrayList Common Properties for:

bool, indicating whether access to ArrayList is synchronized

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capacity	Get or set the length ArrayList can reach
count	Get the actual length of the ArrayList object
isfixedsize	bool, indicating whether ArrayList has a fixed size
isreadonly	bool, indicating whether ArrayList is read-only
issynchronized
item	Get or set the element at the specified index
SyncRoot	Gets the object that can be used to synchronize ArrayList access

ArrayList element Additions:

? ? the Add () and Insert () methods are provided in ArrayList for adding elements to the ArrayList Collection :

? ? [1]. ADD ():// or AddRange ()

? ? ? ? Add () cannot specify the location of elements added to the collection , typically at the end of the ArrayList collection.

? ? ? ? Syntax:

? ? ? ? Arraylist.add (Object value);

? ? ? ? Arraylist.addrange (Array)

? ? ? ? ?//value: to add to The Object at the end of the ArrayList , which can be a null reference and also allows duplicate values ;

? ? [2]. Insert ():// or insert

? ? ? ? The Insert () method is used to add elements to the collection at the specified position ( in index )

? ? ? ? Syntax:

? ? ? ? Arraylist.insert (int index, Object value);

? ? ? ?? //index: from 0 -Starting index

???? ?//value: with Add ()

? ? ? ? Description:

? ? ? ? If you say ArrayList the number of elements actually stored is equal to ArrayList number of elements that can be stored , is incremented by automatically reallocating the internal array ArrayList of Capacity ( i.e. length ), and copy the existing elements between the new elements into the new array.

? ? ? ? ? ???

ArrayList with the Array conversion of each other:

ArrayList Overview of C #