DrawingVisual.RenderOpen Metode

Definisi

Ruang nama:

System.Windows.Media

Rakitan:

PresentationCore.dll

Membuka objek untuk penyajian DrawingVisual . Nilai yang dikembalikan DrawingContext dapat digunakan untuk merender ke DrawingVisualdalam .

public:
 System::Windows::Media::DrawingContext ^ RenderOpen();

public System.Windows.Media.DrawingContext RenderOpen();

member this.RenderOpen : unit -> System.Windows.Media.DrawingContext

Public Function RenderOpen () As DrawingContext

Mengembalikan

DrawingContext

Nilai jenis DrawingContext.

Contoh

Dalam contoh berikut, DrawingVisual objek dibuat, dan DrawingContext dikembalikan.

// Create a DrawingVisual that contains a rectangle.
private DrawingVisual CreateDrawingVisualRectangle()
{
    DrawingVisual drawingVisual = new DrawingVisual();

    // Retrieve the DrawingContext in order to create new drawing content.
    DrawingContext drawingContext = drawingVisual.RenderOpen();

    // Create a rectangle and draw it in the DrawingContext.
    Rect rect = new Rect(new System.Windows.Point(160, 100), new System.Windows.Size(320, 80));
    drawingContext.DrawRectangle(System.Windows.Media.Brushes.LightBlue, (System.Windows.Media.Pen)null, rect);

    // Persist the drawing content.
    drawingContext.Close();

    return drawingVisual;
}

' Create a DrawingVisual that contains a rectangle.
Private Function CreateDrawingVisualRectangle() As DrawingVisual
    Dim drawingVisual As New DrawingVisual()

    ' Retrieve the DrawingContext in order to create new drawing content.
    Dim drawingContext As DrawingContext = drawingVisual.RenderOpen()

    ' Create a rectangle and draw it in the DrawingContext.
    Dim rect As New Rect(New Point(160, 100), New Size(320, 80))
    drawingContext.DrawRectangle(Brushes.LightBlue, CType(Nothing, Pen), rect)

    ' Persist the drawing content.
    drawingContext.Close()

    Return drawingVisual
End Function

Urutan Anda menggambar ke dalam konteks gambar penting - setiap gambar yang berhasil digambar di atas yang lain. Dalam contoh berikut, persegi panjang digambar terlebih dahulu, lalu teks.

// Retrieve the DrawingContext in order to draw into the visual object.
DrawingContext drawingContext = drawingVisual.RenderOpen();

// Draw a rectangle into the DrawingContext.
Rect rect = new Rect(new Point(160, 100), new Size(320, 80));
drawingContext.DrawRectangle(Brushes.LightBlue, (Pen)null, rect);

// Draw a formatted text string into the DrawingContext.
drawingContext.DrawText(
   new FormattedText("Hello, world",
      CultureInfo.GetCultureInfo("en-us"),
      FlowDirection.LeftToRight,
      new Typeface("Verdana"),
      36, Brushes.Black),
      new Point(200, 116));

// Persist the drawing content.
drawingContext.Close();

' Retrieve the DrawingContext in order to draw into the visual object.
Dim drawingContext As DrawingContext = drawingVisual.RenderOpen()

' Draw a rectangle into the DrawingContext.
Dim rect As New Rect(New Point(160, 100), New Size(320, 80))
drawingContext.DrawRectangle(Brushes.LightBlue, CType(Nothing, Pen), rect)

' Draw a formatted text string into the DrawingContext.
drawingContext.DrawText(New FormattedText("Hello, world", CultureInfo.GetCultureInfo("en-us"), FlowDirection.LeftToRight, New Typeface("Verdana"), 36, Brushes.Black), New Point(200, 116))

' Persist the drawing content.
drawingContext.Close()

Keterangan

Ketika Anda memanggil Close metode DrawingContext, konten gambar saat ini menggantikan konten gambar sebelumnya yang ditentukan untuk DrawingVisual. Ini berarti bahwa tidak ada cara untuk menambahkan konten gambar baru ke konten gambar yang ada.

Lihat juga

• Uji Tabrakan Menggunakan DrawingVisuals Sample