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 InverseReferenceSet<T>

Represents a set of inverse references.

Inheritance

System.Object

InverseReferenceSet

InverseReferenceSet<T>

Implements

System.Collections.Generic.ICollection<T>

System.Collections.Generic.IEnumerable<T>

System.Collections.IEnumerable

System.Collections.Generic.IReadOnlyList<T>

System.Collections.Generic.IReadOnlyCollection<T>

Namespace: VeloxDB.ObjectInterface

Assembly: vlxdb.dll

Syntax

public sealed class InverseReferenceSet<T> : InverseReferenceSet, ICollection<T>, IEnumerable<T>, IEnumerable, IReadOnlyList<T>, IReadOnlyCollection<T> where T : DatabaseObject

Type Parameters

Name	Description
T	The type of items in the array.

Examples

The following example demonstrates how to declare an InverseReferencesAttribute property.

[DatabaseClass]
public abstract class Blog : DatabaseObject
{
    [DatabaseProperty]
    public abstract string Url { get; set; }

    [InverseReferences(nameof(Post.Blog))]
    public abstract InverseReferenceSet<Post> Posts { get; }
}

The following example demonstrates how to use an InverseReferenceSet<T>.

[DbAPIOperation]
public bool TestBlog(ObjectModel om)
{
    bool result = true;
    // Create new blog.
    Blog blog = om.CreateObject<Blog>();

    // Create a new post.
    Post post1 = om.CreateObject<Post>();

    // Add a new post using direct reference.
    post1.Blog = blog;

    // Create another post.
    Post post2 = om.CreateObject<Post>();

    // Add another post to the blog, using inverse reference.
    blog.Posts.Add(post2);

    // Check if both posts are in blog
    result &= blog.Posts.Contains(post1);
    result &= blog.Posts.Contains(post2);

    // Check if both posts reference blog
    result &= post1.Blog == blog;
    result &= post2.Blog == blog;

    // Clear all posts
    blog.Posts.Clear();

    // Confirm that posts are not in blog anymore.
    result &= !blog.Posts.Contains(post1);
    result &= !blog.Posts.Contains(post2);

    // Check if both posts point to null.
    result &= post1.Blog == null;
    result &= post2.Blog == null;

    // Delete posts.
    post1.Delete();
    post2.Delete();

    // Delete blog.
    blog.Delete();

    return result;
}

Properties

Count

Gets the number of items in InverseReferenceSet<T>

Declaration

public override int Count { get; }

Property Value

Type	Description
System.Int32

Overrides

InverseReferenceSet.Count

IsReadOnly

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

Declaration

public bool IsReadOnly { get; }

Property Value

Type	Description
System.Boolean

Item[Int32]

Index accessor.

Declaration

public T this[int index] { get; }

Parameters

Type	Name	Description
System.Int32	index	Index of the item to get.

Property Value

Type	Description
T	Requested item.

Exceptions

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

Methods

Add(T)

Add an item to InverseReferenceSet<T>.

Declaration

public void Add(T item)

Parameters

Type	Name	Description
T	item	The item to be added.

Remarks

This is the same as creating a direct reference.

note

Order in InverseReferenceSet<T> is not guaranteed. Added object can appear anywhere in InverseReferenceSet<T>.

Exceptions

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

Clear()

Clears all references.

Declaration

public void Clear()

Exceptions

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

Contains(T)

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

Declaration

public bool Contains(T item)

Parameters

Type	Name	Description
T	item

Returns

Type	Description
System.Boolean	`true` if item is present in the InverseReferenceSet<T>, false if not.

Exceptions

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

CopyTo(T[], Int32)

Copies all items from the InverseReferenceSet<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.
System.Int32	arrayIndex	Zero based index in `array` at which copying begins.

Exceptions

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

GetEnumerator()

Returns an enumerator that iterates through InverseReferenceSet<T>.

Declaration

public IEnumerator<T> GetEnumerator()

Returns

Type	Description
System.Collections.Generic.IEnumerator<T>	An enumerator.

Remarks

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

Exceptions

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

ReleaseMemory()

Releases the memory held by InverseReferenceSet<T>.

Declaration

public void ReleaseMemory()

Remarks

InverseReferenceSet<T> is lazy, it will not fetch inverse references until it needs to. Once you access inverse references, it will allocate an array to hold them. You can release this array by calling ReleaseMemory(). Once the array is released, if you once again access the InverseReferenceSet<T> it will allocate memory again.

Remove(T)

Remove an item from InverseReferenceSet<T>.

Declaration

public bool Remove(T item)

Parameters

Type	Name	Description
T	item	Item to remove.

Returns

Type	Description
System.Boolean	`true` if `item` was removed, otherwise if item is not found, it returns `false`.

Remarks

This is the same as removing the direct reference.

Exceptions

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

Implements

System.Collections.Generic.ICollection<>

System.Collections.Generic.IEnumerable<>

System.Collections.IEnumerable

System.Collections.Generic.IReadOnlyList<>

System.Collections.Generic.IReadOnlyCollection<>