ArrayList represents an ordered collection of an object that can be indexed individually. It is basically an alternative to an array. It also allows dynamic memory allocation, adding, searching and sorting items in the list. ArrayList.Insert(Int32, Object) method inserts an element into the ArrayList at the specified index.
Properties of ArrayList Class:
- Elements can be added or removed from the Array List collection at any point in time.
- The ArrayList is not guaranteed to be sorted.
- The capacity of an ArrayList is the number of elements the ArrayList can hold.
- Elements in this collection can be accessed using an integer index. Indexes in this collection are zero-based.
- It also allows duplicate elements.
- Using multidimensional arrays as elements in an ArrayList collection is not supported.
public virtual void Insert (int index, object value);
index : It is the zero-based index at which value should be inserted.
value : It is the Object which is to be inserted. The value can be null.
- ArgumentOutOfRangeException : If index is less than zero or index is greater than Count i.e, number of elements in the ArrayList.
- NotSupportedException : If the ArrayList is read-only or the ArrayList has a fixed size.
Below given are some examples to understand the implementation in a better way:
The initial ArrayList is : A B C The ArrayList after Inserting elements is : A D B C E F
The initial ArrayList is : 1 2 3 The ArrayList after Inserting elements is : 6 5 4 1 2 3
- If index is equal to Count i.e, number of elements in the ArrayList, value is added to the end of ArrayList.
- This method is an O(n) operation, where n is Count.
- C# | Get or set the element at the specified index in ArrayList
- C# | Remove the element at the specified index of the ArrayList
- C# | Insert an element into Collection<T> at specified index
- C# | Insert into OrderedDictionary with key and value at specified index
- C# | Insert at the specified index in StringCollection
- C# | How to insert the elements of a collection into the List at the specified index
- C# | Copying the entire ArrayList to 1-D Array starting at the specified index
- C# | Check whether an element is contained in the ArrayList
- C# | Get or set the element at specified index in Collection<T>
- C# | Finding the index of first element in the array
- C# | Gets or sets the element at the specified index in StringCollection
- C# | How to remove the element from the specified index of the List
- C# | Gets or Sets the element at the specified index in the List
- C# | Finding the index of last element in the array
- C# | Remove element at specified index of Collection<T>
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to firstname.lastname@example.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.