BitmapCacheOption 枚举

定义

指定位图图像如何利用内存缓存。Specifies how a bitmap image takes advantage of memory caching.

public enum class BitmapCacheOption
public enum BitmapCacheOption
type BitmapCacheOption = 
Public Enum BitmapCacheOption
继承
BitmapCacheOption

字段

Default 0

将整个图像缓存到内存中。Caches the entire image into memory. 这是默认值。This is the default value.

None 2

不创建内存存储。Do not create a memory store. 对图像的所有请求均由图像文件直接填充。All requests for the image are filled directly by the image file.

OnDemand 0

只为请求的数据创建内存存储。Creates a memory store for requested data only. 第一个请求直接加载图像;后续请求将通过缓存进行填充。The first request loads the image directly; subsequent requests are filled from the cache.

OnLoad 1

在加载时将整个图像缓存到内存中。Caches the entire image into memory at load time. 对图像数据的所有请求将通过内存存储进行填充。All requests for image data are filled from the memory store.

示例

下面的代码示例演示如何加载BitmapImageBitmapCacheOption指定。The following code example demonstrates how to load a BitmapImage and specify the BitmapCacheOption.

// Define a BitmapImage.
Image myImage = new Image();
BitmapImage bi = new BitmapImage();

// Begin initialization.
bi.BeginInit();

// Set properties.
bi.CacheOption = BitmapCacheOption.OnDemand;
bi.CreateOptions = BitmapCreateOptions.DelayCreation;
bi.DecodePixelHeight = 125;
bi.DecodePixelWidth = 125;
bi.Rotation = Rotation.Rotate90;
MessageBox.Show(bi.IsDownloading.ToString());
bi.UriSource = new Uri("smiley.png", UriKind.Relative);

// End initialization.
bi.EndInit();
myImage.Source = bi;
myImage.Stretch = Stretch.None;
myImage.Margin = new Thickness(5);
' Define a BitmapImage.
Dim myImage As New Image()
Dim bi As New BitmapImage()

' Begin initialization.
bi.BeginInit()

' Set properties.
bi.CacheOption = BitmapCacheOption.OnDemand
bi.CreateOptions = BitmapCreateOptions.DelayCreation
bi.DecodePixelHeight = 125
bi.DecodePixelWidth = 125
bi.Rotation = Rotation.Rotate90
MessageBox.Show(bi.IsDownloading.ToString())
bi.UriSource = New Uri("smiley.png", UriKind.Relative)

' End initialization.
bi.EndInit()
myImage.Source = bi
myImage.Stretch = Stretch.None
myImage.Margin = New Thickness(5)

适用于

另请参阅