VisualTreeHelper.GetDrawing(Visual) Metode

Definisi

Ruang nama:

System.Windows.Media

Rakitan:

PresentationCore.dll

Mengembalikan konten gambar dari yang ditentukan 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

Konten Visual gambar yang dikembalikan.

Mengembalikan

DrawingGroup

Konten gambar yang Visual dikembalikan sebagai DrawingGroup jenis.

Contoh

Contoh berikut menunjukkan cara mengambil DrawingGroup dari objek visual dengan menggunakan GetDrawing metode . Tes hit kemudian dilakukan pada geometri setiap gambar di DrawingGroup untuk menentukan geometri mana yang terpukul.

// Determine if a geometry within the visual was hit.
public static 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.
public static 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