VisualTreeHelper.GetDrawing(Visual) VisualTreeHelper.GetDrawing(Visual) VisualTreeHelper.GetDrawing(Visual) VisualTreeHelper.GetDrawing(Visual) Method

Definition

Returns the drawing content of the specified Visual.

public:
 static System::Windows::Media::DrawingGroup ^ GetDrawing(System::Windows::Media::Visual ^ reference);
public static System.Windows.Media.DrawingGroup GetDrawing (System.Windows.Media.Visual reference);
static member GetDrawing : System.Windows.Media.Visual -> System.Windows.Media.DrawingGroup
Public Shared Function GetDrawing (reference As Visual) As DrawingGroup

Parameters

reference
Visual Visual Visual Visual

The Visual whose drawing content is returned.

Returns

The drawing content of the Visual returned as a DrawingGroup type.

Examples

The following example shows how to retrieve the DrawingGroup from a visual object by using the GetDrawing method. A hit test is then performed on the geometry of each drawing in the DrawingGroup to determine which geometry was hit.

// Determine if a geometry within the visual was hit.
static public void HitTestGeometryInVisual(Visual visual, Point pt)
{
    // Retrieve the group of drawings for the visual.
    DrawingGroup drawingGroup = VisualTreeHelper.GetDrawing(visual);
    EnumDrawingGroup(drawingGroup, pt);
}

// Enumerate the drawings in the DrawingGroup.
static public void EnumDrawingGroup(DrawingGroup drawingGroup, Point pt)
{
    DrawingCollection drawingCollection = drawingGroup.Children;

    // Enumerate the drawings in the DrawingCollection.
    foreach (Drawing drawing in drawingCollection)
    {
        // If the drawing is a DrawingGroup, call the function recursively.
        if (drawing.GetType() == typeof(DrawingGroup))
        {
            EnumDrawingGroup((DrawingGroup)drawing, pt);
        }
        else if (drawing.GetType() == typeof(GeometryDrawing))
        {
            // Determine whether the hit test point falls within the geometry.
            if (((GeometryDrawing)drawing).Geometry.FillContains(pt))
            {
                // Perform action based on hit test on geometry.
            }
        }

    }
}
' Determine if a geometry within the visual was hit.
Public Shared Sub HitTestGeometryInVisual(ByVal visual As Visual, ByVal pt As Point)
	' Retrieve the group of drawings for the visual.
	Dim drawingGroup As DrawingGroup = VisualTreeHelper.GetDrawing(visual)
	EnumDrawingGroup(drawingGroup, pt)
End Sub

' Enumerate the drawings in the DrawingGroup.
Public Shared Sub EnumDrawingGroup(ByVal drawingGroup As DrawingGroup, ByVal pt As Point)
	Dim drawingCollection As DrawingCollection = drawingGroup.Children

	' Enumerate the drawings in the DrawingCollection.
	For Each drawing As Drawing In drawingCollection
		' If the drawing is a DrawingGroup, call the function recursively.
		If drawing.GetType() Is GetType(DrawingGroup) Then
			EnumDrawingGroup(CType(drawing, DrawingGroup), pt)
		ElseIf drawing.GetType() Is GetType(GeometryDrawing) Then
			' Determine whether the hit test point falls within the geometry.
			If (CType(drawing, GeometryDrawing)).Geometry.FillContains(pt) Then
				' Perform action based on hit test on geometry.
			End If
		End If

	Next drawing
End Sub

Applies to