VisualCollection.Add(Visual) Method

public:
 int Add(System::Windows::Media::Visual ^ visual);

public int Add(System.Windows.Media.Visual visual);

member this.Add : System.Windows.Media.Visual -> int

Public Function Add (visual As Visual) As Integer

Parameters

Returns

The index in the collection at which visual was added.

Exceptions

Examples

The following example shows how to create a VisualCollection and add members to it.

// Create a host visual derived from the FrameworkElement class.
// This class provides layout, event handling, and container support for
// the child visual objects.
public class MyVisualHost : FrameworkElement
{
 // Create a collection of child visual objects.
 private VisualCollection _children;

 public MyVisualHost()
 {
 _children = new VisualCollection(this);
 _children.Add(CreateDrawingVisualRectangle());
 _children.Add(CreateDrawingVisualText());
 _children.Add(CreateDrawingVisualEllipses());

 // Add the event handler for MouseLeftButtonUp.
 this.MouseLeftButtonUp += new System.Windows.Input.MouseButtonEventHandler(MyVisualHost_MouseLeftButtonUp);
 }

' Create a host visual derived from the FrameworkElement class.
' This class provides layout, event handling, and container support for
' the child visual objects.
Public Class MyVisualHost
 Inherits FrameworkElement
 ' Create a collection of child visual objects.
 Private _children As VisualCollection

 Public Sub New()
 _children = New VisualCollection(Me)
 _children.Add(CreateDrawingVisualRectangle())
 _children.Add(CreateDrawingVisualText())
 _children.Add(CreateDrawingVisualEllipses())

 ' Add the event handler for MouseLeftButtonUp.
 AddHandler MouseLeftButtonUp, AddressOf MyVisualHost_MouseLeftButtonUp
 End Sub

Remarks

Adding a Visual whose value is null is permitted and does not raise an exception.

The Add method also sets up the parent-child relationship between the parent visual, which is the owner of the VisualCollection, and the child visual.

If you need greater low-level control over the underlying storage implementation of visual child objects of a custom class, consider using the AddVisualChild and RemoveVisualChild methods. When you use these methods, you must define your own storage implementation, and do not use VisualCollection.