VisualTreeHelper.GetDrawing(Visual) Methode

Definition

Gibt den Zeichnungsinhalt des angegebenen Visual zurück.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

Parameter

reference
Visual

Das Visual, dessen Zeichnungsinhalt zurückgegeben wird.The Visual whose drawing content is returned.

Gibt zurück

Der als Visual-Typ zurückgegebene Zeichnungsinhalt des DrawingGroup.The drawing content of the Visual returned as a DrawingGroup type.

Beispiele

Im folgenden Beispiel wird gezeigt, wie der DrawingGroup mithilfe der GetDrawing -Methode aus einem visuellen Objekt abgerufen wird.The following example shows how to retrieve the DrawingGroup from a visual object by using the GetDrawing method. Anschließend wird ein Treffer Test für die Geometrie der einzelnen Zeichnungen in DrawingGroup ausgeführt, um zu bestimmen, welche Geometrie getroffen wurde.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

Gilt für: