FormatConvertedBitmap.BeginInit Metodo
Definizione
Importante
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Segnala l'avvio dell'inizializzazione dell'oggetto FormatConvertedBitmap.
public:
virtual void BeginInit();public void BeginInit ();abstract member BeginInit : unit -> unit
override this.BeginInit : unit -> unitPublic Sub BeginInit ()Implementazioni
Eccezioni
FormatConvertedBitmap è attualmente in fase di inizializzazione. Il metodo BeginInit() è già stato chiamato.
-oppure- L'oggetto FormatConvertedBitmap è già stato inizializzato.
Esempio
Nell'esempio seguente viene illustrato come inizializzare un FormatConvertedBitmap oggetto con un set di proprietà usando i BeginInit metodi e EndInit .
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Imaging;
namespace SDKSample
{
public partial class FormatConvertedBitmapExample : Page
{
public FormatConvertedBitmapExample()
{
///// Create a BitmapImage and set it's DecodePixelWidth to 200. Use /////
///// this BitmapImage as a source for other BitmapSource objects. /////
BitmapImage myBitmapImage = new BitmapImage();
// BitmapSource objects like BitmapImage can only have their properties
// changed within a BeginInit/EndInit block.
myBitmapImage.BeginInit();
myBitmapImage.UriSource = new Uri(@"sampleImages/WaterLilies.jpg",UriKind.Relative);
// To save significant application memory, set the DecodePixelWidth or
// DecodePixelHeight of the BitmapImage value of the image source to the desired
// height or width of the rendered image. If you don't do this, the application will
// cache the image as though it were rendered as its normal size rather then just
// the size that is displayed.
// Note: In order to preserve aspect ratio, set DecodePixelWidth
// or DecodePixelHeight but not both.
myBitmapImage.DecodePixelWidth = 200;
myBitmapImage.EndInit();
////////// Convert the BitmapSource to a new format ////////////
// Use the BitmapImage created above as the source for a new BitmapSource object
// which is set to a gray scale format using the FormatConvertedBitmap BitmapSource.
// Note: New BitmapSource does not cache. It is always pulled when required.
FormatConvertedBitmap newFormatedBitmapSource = new FormatConvertedBitmap();
// BitmapSource objects like FormatConvertedBitmap can only have their properties
// changed within a BeginInit/EndInit block.
newFormatedBitmapSource.BeginInit();
// Use the BitmapSource object defined above as the source for this new
// BitmapSource (chain the BitmapSource objects together).
newFormatedBitmapSource.Source = myBitmapImage;
// Set the new format to Gray32Float (grayscale).
newFormatedBitmapSource.DestinationFormat = PixelFormats.Gray32Float;
newFormatedBitmapSource.EndInit();
// Create Image Element
Image myImage = new Image();
myImage.Width = 200;
//set image source
myImage.Source = newFormatedBitmapSource;
// Add Image to the UI
StackPanel myStackPanel = new StackPanel();
myStackPanel.Children.Add(myImage);
this.Content = myStackPanel;
}
}
}
Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Media
Imports System.Windows.Media.Imaging
Namespace SDKSample
Class FormatConvertedBitmapExample
Inherits Page
Public Sub New()
'/// Create a BitmapImage and set it's DecodePixelWidth to 200. Use /////
'/// this BitmapImage as a source for other BitmapSource objects. /////
Dim myBitmapImage As New BitmapImage()
' BitmapSource objects like BitmapImage can only have their properties
' changed within a BeginInit/EndInit block.
myBitmapImage.BeginInit()
myBitmapImage.UriSource = New Uri("sampleImages/WaterLilies.jpg", UriKind.Relative)
' To save significant application memory, set the DecodePixelWidth or
' DecodePixelHeight of the BitmapImage value of the image source to the desired
' height or width of the rendered image. If you don't do this, the application will
' cache the image as though it were rendered as its normal size rather then just
' the size that is displayed.
' Note: In order to preserve aspect ratio, set DecodePixelWidth
' or DecodePixelHeight but not both.
myBitmapImage.DecodePixelWidth = 200
myBitmapImage.EndInit()
'//////// Convert the BitmapSource to a new format ////////////
' Use the BitmapImage created above as the source for a new BitmapSource object
' which is set to a gray scale format using the FormatConvertedBitmap BitmapSource.
' Note: New BitmapSource does not cache. It is always pulled when required.
Dim newFormatedBitmapSource As New FormatConvertedBitmap()
' BitmapSource objects like FormatConvertedBitmap can only have their properties
' changed within a BeginInit/EndInit block.
newFormatedBitmapSource.BeginInit()
' Use the BitmapSource object defined above as the source for this new
' BitmapSource (chain the BitmapSource objects together).
newFormatedBitmapSource.Source = myBitmapImage
' Set the new format to Gray32Float (grayscale).
newFormatedBitmapSource.DestinationFormat = PixelFormats.Gray32Float
newFormatedBitmapSource.EndInit()
' Create Image Element
Dim myImage As New Image()
myImage.Width = 200
'set image source
myImage.Source = newFormatedBitmapSource
' Add Image to the UI
Dim myStackPanel As New StackPanel()
myStackPanel.Children.Add(myImage)
Me.Content = myStackPanel
End Sub
End Class
End Namespace 'ImagingSnippetGallery
Commenti
L'inizializzazione delle proprietà deve essere eseguita tra BeginInit le chiamate e EndInit . Dopo l'inizializzazione FormatConvertedBitmap di , le modifiche alle proprietà vengono ignorate.