note

VeloxDB is still in beta and APIs are subject to change. We are in the process of completing the documentation, so some sections may be incomplete or empty at this time.

Class ReferenceArray<T>

Represents an array of references to database objects.

Inheritance

object

ReferenceArray

ReferenceArray<T>

Implements

IList<T>

ICollection<T>

IEnumerable<T>

IEnumerable

Inherited Members

object.GetType()

object.ToString()

object.Equals(object)

object.Equals(object, object)

object.ReferenceEquals(object, object)

object.GetHashCode()

Namespace: VeloxDB.ObjectInterface

Assembly: vlxdb.dll

Syntax

public sealed class ReferenceArray<T> : ReferenceArray, IList<T>, ICollection<T>, IEnumerable<T>, IEnumerable where T : DatabaseObject

Type Parameters

Name	Description
T	The type of items in the array.

Remarks

VeloxDB allows you to specify an array like collection. ReferenceArray<T> can only hold references to DatabaseObject, if you need an array of references to simple types, use DatabaseArray<T>. ReferenceArray<T> property must be marked with DatabaseReferenceAttribute attribute because it represents a reference to another DatabaseObject.

ReferenceArray<T> is backed by an array. Array's size is initially set to capacity. As long as the capacity is larger than the length of the array Add is constant time operation (O(1)). When there is no more space in the backing array new array is allocated. The new array is twice the size of the previous one. Contents of the old array are copied to the new array. This gives ReferenceArray<T> amortized constant time adds, constant time direct access and linear remove.

Examples

The following example demonstrates how to declare a ReferenceArray<T> property.

[DatabaseClass]
[HashIndex("name", true, nameof(City.Name))]
public abstract class City : DatabaseObject
{
    [DatabaseProperty]
    public abstract string Name { get; set; }

    [DatabaseReference]
    public abstract ReferenceArray<WeatherStation> Stations {get; set;}
}

The following example demonstrates how to use a ReferenceArray<T>.

[DbAPIOperation]
public void CreateTestCity(ObjectModel om)
{
    City city = om.CreateObject<City>();

    city.Stations = new ReferenceArray<WeatherStation>();

    WeatherStation ws;
    for (int i = 0; i < 4; i++)
    {
        ws = om.CreateObject<WeatherStation>();
        city.Stations.Add(ws);
    }

    // Get a WeatherStation by index
    ws = city.Stations[2];

    // Remove using object
    city.Stations.Remove(ws);

    // Remove using index
    city.Stations.RemoveAt(0);

    // Clear
    city.Stations.Clear();
}

Constructors

ReferenceArray()

Creates a new empty instance of the ReferenceArray<T>.

Declaration

public ReferenceArray()

ReferenceArray(IEnumerable<T>)

Creates a new instance of the ReferenceArray<T> that contains elements copied from the supplied collection.

Declaration

public ReferenceArray(IEnumerable<T> collection)

Parameters

Type	Name	Description
IEnumerable<T>	collection	The collection whose elements are to be copied.

Exceptions

Type	Condition
ArgumentNullException	collection is null or an item in the collection is null.
ArgumentException	If any item in collection is a deleted item.

ReferenceArray(int)

Creates a new empty instance of the ReferenceArray<T>. With specified capacity.

Declaration

public ReferenceArray(int capacity = 4)

Parameters

Type	Name	Description
int	capacity	Initial capacity. The initial size of the backing array.

Properties

Count

Gets the number of items contained in the ReferenceArray<T>.

Declaration

public override int Count { get; }

Property Value

Type	Description
int

Overrides

ReferenceArray.Count

Exceptions

Type	Condition
InvalidOperationException	If the parent object of the DatabaseArray<T> has been deleted or abandoned.
ObjectDisposedException	If the parent object of the DatabaseArray<T> has been disposed.

IsReadOnly

Gets if the ReferenceArray<T> is Readonly. Always returns false.

Declaration

public bool IsReadOnly { get; }

Property Value

Type	Description
bool

this[int]

Index accessor.

Declaration

public T this[int index] { get; set; }

Parameters

Type	Name	Description
int	index	Index of the item to get.

Property Value

Type	Description
T	Requested item.

Exceptions

Type	Condition
IndexOutOfRangeException	If index is less than 0 or greater than Count
InvalidOperationException	If the parent object of the DatabaseArray<T> has been deleted or abandoned.
ObjectDisposedException	If the parent object of the DatabaseArray<T> has been disposed.

Methods

Add(T)

Add an item to the end of the ReferenceArray<T>.

Declaration

public void Add(T item)

Parameters

Type	Name	Description
T	item	The item to be added to the end of the ReferenceArray<T>.

Exceptions

Type	Condition
ArgumentNullException	item is null
InvalidOperationException	If the added item would cause Count to exceed int.MaxValue or If the parent object of the ReferenceArray<T> has been deleted or abandoned.
ObjectDisposedException	If the parent object of the ReferenceArray<T> has been disposed.

AddRange(IEnumerable<T>)

Adds the elements of the specified collection to the end of the DatabaseArray<T>.

Declaration

public void AddRange(IEnumerable<T> collection)

Parameters

Type	Name	Description
IEnumerable<T>	collection	Collection whose elements will be added.

Exceptions

Type	Condition
ArgumentNullException	collection is null.

Clear()

Clears the ReferenceArray<T>.

Declaration

public void Clear()

Exceptions

Type	Condition
InvalidOperationException	If the parent object of the ReferenceArray<T> has been deleted or abandoned.
ObjectDisposedException	If the parent object of the ReferenceArray<T> has been disposed.

Contains(T)

Determines if an item is in the ReferenceArray<T>.

Declaration

public bool Contains(T item)

Parameters

Type	Name	Description
T	item	The item to locate in the ReferenceArray<T>.

Returns

Type	Description
bool	true if item is present in the ReferenceArray<T>, false if not.

Exceptions

Type	Condition
ArgumentNullException	item is null.
InvalidOperationException	If the parent object of the ReferenceArray<T> has been deleted or abandoned.
ObjectDisposedException	If the parent object of the ReferenceArray<T> has been disposed.

CopyTo(T[], int)

Copies all items from the ReferenceArray<T> to the given array, starting at the specified index of the target array.

Declaration

public void CopyTo(T[] array, int arrayIndex)

Parameters

Type	Name	Description
T[]	array	Destination array.
int	arrayIndex	Zero based index in array at which copying begins.

Exceptions

Type	Condition
ArgumentNullException	array is null.
ArgumentException	There is not enough space in array to accommodate all the items.
ArgumentOutOfRangeException	arrayIndex is less than 0.
InvalidOperationException	If the parent object of the ReferenceArray<T> has been deleted or abandoned.
ObjectDisposedException	If the parent object of the ReferenceArray<T> has been disposed.

GetEnumerator()

Returns an enumerator that iterates through ReferenceArray<T>.

Declaration

public IEnumerator<T> GetEnumerator()

Returns

Type	Description
IEnumerator<T>	An enumerator.

Remarks

If ReferenceArray<T> changes, enumerator is invalidated. Any attempts to use it after that will throw an InvalidOperationException.

Exceptions

Type	Condition
InvalidOperationException	If the parent object of the ReferenceArray<T> has been deleted or abandoned.
ObjectDisposedException	If the parent object of the ReferenceArray<T> has been disposed.

IndexOf(T)

Finds an item in the ReferenceArray<T> and returns its position.

Declaration

public int IndexOf(T item)

Parameters

Type	Name	Description
T	item	Item to find in ReferenceArray<T>.

Returns

Type	Description
int	If the element is found, it return the zero based index in ReferenceArray<T>, otherwise it returns -1.

Exceptions

Type	Condition
ArgumentNullException	item is null.
InvalidOperationException	If the parent object of the ReferenceArray<T> has been deleted or abandoned.
ObjectDisposedException	If the parent object of the ReferenceArray<T> has been disposed.

Insert(int, T)

Inserts an item into ReferenceArray<T> at the specified position.

Declaration

public void Insert(int index, T item)

Parameters

Type	Name	Description
int	index	Zero based position at which to insert item.
T	item	The item to insert.

Exceptions

Type	Condition
ArgumentNullException	item is null.
ArgumentOutOfRangeException	If index is less than 0 or greater than Count
InvalidOperationException	If the parent object of the ReferenceArray<T> has been deleted or abandoned.
ObjectDisposedException	If the parent object of the ReferenceArray<T> has been disposed.

Remove(T)

Remove the first occurrence of the item from the ReferenceArray<T>.

Declaration

public bool Remove(T item)

Parameters

Type	Name	Description
T	item	Item to be removed.

Returns

Type	Description
bool	true if item was removed, otherwise false.

Exceptions

Type	Condition
ArgumentNullException	item is null.
InvalidOperationException	If the parent object of the ReferenceArray<T> has been deleted or abandoned.
ObjectDisposedException	If the parent object of the ReferenceArray<T> has been disposed.

RemoveAt(int)

Remove an item at the given position.

Declaration

public void RemoveAt(int index)

Parameters

Type	Name	Description
int	index	Zero based index of an item to remove.

Exceptions

Type	Condition
ArgumentOutOfRangeException	If index is less than 0 or greater than Count
InvalidOperationException	If the parent object of the DatabaseArray<T> has been deleted or abandoned.
ObjectDisposedException	If the parent object of the DatabaseArray<T> has been disposed.

Implements

IList<T>

ICollection<T>

IEnumerable<T>

IEnumerable

See Also

DatabaseArray<T>

DatabaseReferenceAttribute