Add Method

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Adds an object to the end of the ArrayList.

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

public virtual int Add(
	Object value
)

Parameters

value
Type: System..::..Object
The Object to be added to the end of the ArrayList. The value can be nullNothingnullptrunita null reference (Nothing in Visual Basic).

Return Value

Type: System..::..Int32
The ArrayList index at which the value has been added.

Implements

IList..::..Add(Object)

ArrayList accepts nullNothingnullptrunita null reference (Nothing in Visual Basic) as a valid value and allows duplicate elements.

If Count already equals Capacity, the capacity of the ArrayList is increased by automatically reallocating the internal array, and the existing elements are copied to the new array before the new element is added.

If Count is less than Capacity, this method is an O(1) operation. If the capacity needs to be increased to accommodate the new element, this method becomes an O(n) operation, where n is Count.

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