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ImageCache

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The ImageCache provides methods and tools to cache images in a temporary local folder. ImageCache also supports optional in-memory layer of caching, that provides better performance when same images are requested multiple times (like in long virtualized lists of images). This type of caching is disabled by default, but can be enabled by setting MaxMemoryCacheSize to desired size. For example: setting MaxMemoryCacheSize to 100 means that 100 last requested images will be held in memory to be instantly available, without disk reads.

Try it in the sample app

Syntax

// Set cache duration
ImageCache.Instance.CacheDuration = TimeSpan.FromHours(24);

// Enable in-memory caching
ImageCache.Instance.MaxMemoryCacheCount = 100;

var distantUri = new Uri("https://www.myserver.com/image.jpg");

// Load a specific image from the cache. If the image is not in the cache, ImageCache will try to download and store it
var bitmapImage = await ImageCache.Instance.GetFromCacheAsync(distantUri);

// Clear the cache. Please note that you can provide a parameter to define a timespan from now to select cache entries to delete.
await ImageCache.Instance.ClearAsync(); 

' Set cache duration
ImageCache.Instance.CacheDuration = TimeSpan.FromHours(24)

' Enable in-memory caching
ImageCache.Instance.MaxMemoryCacheCount = 100

Dim distantUri = New Uri("https://www.myserver.com/image.jpg")

' Load a specific image from the cache. If the image is not in the cache, ImageCache will try to download and store it
Dim bitmapImage = Await ImageCache.Instance.GetFromCacheAsync(distantUri)

' Clear the cache. Please note that you can provide a parameter to define a timespan from now to select cache entries to delete.
Await ImageCache.Instance.ClearAsync()

Properties

Property Type Description
CacheDuration TimeSpan Gets or sets the life duration of every cache entry
HttpClient HttpClient Gets instance of HttpClient
Instance ImageCache Gets public singleton property
MaintainContext bool Gets or sets a value indicating whether context should be maintained until type has been instantiated or not
MaxMemoryCacheCount int Gets or sets max in-memory item storage count
RetryCount uint Gets or sets the number of retries trying to ensure the file is cached

Methods

Methods Return Type Description
ClearAsync() Task Clears all files in the cache
ClearAsync(TimeSpan) Task Clears file if it has expired
GetFileFromCacheAsync(Uri) Task<StorageFile> Gets the StorageFile containing cached item for given Uri
GetFromCacheAsync(Uri, Boolean, CancellationToken, List<KeyValuePair<string, object>>) Task<T> Retrieves item represented by Uri from the cache. If the item is not found in the cache, it will try to downloaded and saved before returning it to the caller
GetFromMemoryCache(Uri) T Retrieves item represented by Uri from the in-memory cache if it exists and is not out of date. If item is not found or is out of date, default instance of the generic type is returned
PreCacheAsync(Uri, Boolean, Boolean, CancellationToken) Task Assures that item represented by Uri is cached
RemoveAsync(IEnumerable) Task Removed items based on uri list passed
RemoveExpiredAsync(Nullable) Task Removes cached files that have expired

Sample Project

Image Cache Sample Page Source. You can see this in action in the Windows Community Toolkit Sample App.

Requirements

Device family Universal, 10.0.16299.0 or higher
Namespace Microsoft.Toolkit.Uwp
NuGet package Microsoft.Toolkit.Uwp

API