C# Arraylist Tutorial For Beginners With Examples

An Arraylist is a collection which can store any item of type object. The number of objects can dynamically increase or decrease.

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Important features of C# Arraylist class

Below are some of the important features of an Arraylist class.

• Arraylist is a weakly typed collection object.
• Arraylist may or may not be sorted by default.
• It can store billions of elements.
• To access an item in an Arraylist indexes are used.
• It allows null values.
• It allows duplicate elements.
• Performance wise Arraylist is slower compared to generic List.

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Create a C# Arraylist object

An Arraylist can be created by using the below code.

    ArrayList list = new ArrayList();
        

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Add and remove items from C# Arraylist

When writing programs using Arraylist two most common operations performed are adding and removing items.

    list.Add("Hello");
    list.Remove("Hello");
        

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For Loop to access items in C# Arraylist

To display items stored in an Arraylist a loop can be used.

    ArrayList list = new ArrayList();

    list.Add("Hello");
    list.Add("Universe");

    for (int count = 0; count < list.Count; count++)
    {
        Console.WriteLine(list[count]);
    }
        

Output:
Hello
Universe

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Methods and Properties of a C# Arraylist

Commonly used methods of an Arraylist are:

Method	Description
Add	Adds an item at the end of an Arraylist.
AddRange	Adds the elements of an collection to the end of an Arraylist.
Clear	Removes all the elements from an Arraylist.
Contains	Checks if an item is present in an Arraylist.
IndexOf(Object)	Determines the position of an object and returns the zero-based index of that object in an Arraylist.
Insert	Inserts an item in an Arraylist at a specified index.
InsertRange	Inserts the elements of an collection at a specific index of an Arraylist.
Remove	Searches for an item and removes the first occurrence of that item from an Arraylist.
RemoveAt	Removes an item from an Arraylist at a specific index.
RemoveRange	Removes a contiguous list of items from an ArrayList.
Reverse	Reverses the order of the items present in an Arraylist.
Sort	Sorts the items of an Arraylist.

Commonly used properties of an Arraylist are:

Property	Description
Count	Returns the number of items present in an Arraylist.
IsReadOnly	Returns a boolean value which specifies whether an Arraylist is read-only or not.
Item	This property is used along with an index to get or set a value.