BitmapCacheOption 列舉

定義

指定點陣圖影像如何利用記憶體內部快取。Specifies how a bitmap image takes advantage of memory caching.

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

欄位

Default 0

快取整個影像至記憶體。Caches the entire image into memory. 這是預設值。This is the default value.

None 2

請勿建立記憶體存放區。Do not create a memory store. 該影像的所有要求都直接由影像檔填入。All requests for the image are filled directly by the image file.

OnDemand 0

只為要求的資料建立記憶體存放區。Creates a memory store for requested data only. 第一個要求會直接載入影像;後續的要求會從快取填入。The first request loads the image directly; subsequent requests are filled from the cache.

OnLoad 1

在載入時快取整個影像至記憶體。Caches the entire image into memory at load time. 影像資料的所有要求都會從記憶體存放區填入。All requests for image data are filled from the memory store.

範例

下列程式碼範例示範如何載入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)

適用於

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