Current Property
Collapse the table of content
Expand the table of content

IEnumerator.Current Property

 

Gets the current element in the collection.

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

object Current { get; }

Property Value

Type: System.Object

The current element in the collection.

After an enumerator is created or after the Reset method is called, the MoveNext method must be called to advance the enumerator to the first element of the collection before reading the value of the Current property; otherwise, Current is undefined.

Currentshould throw an InvalidOperationException if the last call to MoveNext returned false, which indicates the end of the collection.

Current does not move the position of the enumerator, and consecutive calls to Current return the same object until either MoveNext or Reset is called.

An enumerator remains valid as long as the collection remains unchanged. If changes are made to the collection, such as adding, modifying, or deleting elements, the enumerator is irrecoverably invalidated and the next call to MoveNext or Reset throws an InvalidOperationException. If the collection is modified between MoveNext and Current, Current returns the element that it is set to, even if the enumerator is already invalidated.

The following code example demonstrates the implementation of the IEnumerator interfaces for a custom collection. In this example, Current is not explicitly called, but it is implemented to support the use of foreach (for each in Visual Basic). This code example is part of a larger example for the IEnumerator interface.

// When you implement IEnumerable, you must also implement IEnumerator.
public class PeopleEnum : IEnumerator
{
    public Person[] _people;

    // Enumerators are positioned before the first element
    // until the first MoveNext() call.
    int position = -1;

    public PeopleEnum(Person[] list)
    {
        _people = list;
    }

    public bool MoveNext()
    {
        position++;
        return (position < _people.Length);
    }

    public void Reset()
    {
        position = -1;
    }

    object IEnumerator.Current
    {
        get
        {
            return Current;
        }
    }

    public Person Current
    {
        get
        {
            try
            {
                return _people[position];
            }
            catch (IndexOutOfRangeException)
            {
                throw new InvalidOperationException();
            }
        }
    }
}

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
Return to top
Show:
© 2016 Microsoft