WPF中的脱机图像缓存

我有一个WPF应用程序 从URL加载图像 当有互联网连接时& 应该从缓存中加载这些图像 当没有活动的internet连接时。

我的 问题 如果没有任何活动的internet连接,则不会缓存图像以在随后的应用程序启动中显示。

我已经找了几个小时,几乎所有可能的组合 CreateOptions &安培; CacheOption ,但同样有问题的结果。

XAML代码如下:

              <Image
                   Width="{Binding MY_TILE_W}" MaxWidth="380" 
                   Height="{Binding MY_TILE_H}" MaxHeight="240" 
                   Stretch="UniformToFill">

                    <Image.CacheMode>
                        <BitmapCache  EnableClearType="False"
                              RenderAtScale="1"
                              SnapsToDevicePixels="False" />
                    </Image.CacheMode>

                    <Image.Source>
                        <BitmapImage UriSource="{Binding ImageUrl}" 
                             CreateOptions="IgnoreImageCache"
                             CacheOption="OnLoad"/>
                    </Image.Source>

                </Image>

再也没有了 C# 代码,除了 Binding 当然是密码。

有没有可能达到我的目的?如果是,请怎么做?

编辑: 我的问题不完全是 this SO post ,如@Wilson的注释所示-因为每次下载图像在我的用例中是不同的,但是 the accepted answer's mentioned CachedImage library 已经部分解决了这个问题。

我换了 Image 阻止 the library's 此用户界面元素:

<cachedImage:Image Grid.Row="0" Grid.ColumnSpan="2"
        Width="{Binding MY_TILE_W}" MaxWidth="380" 
        Height="{Binding MY_TILE_H}" MaxHeight="240" 
        Stretch="UniformToFill"
        ImageUrl="{Binding ImageUrl}"/>

然后,VS 2017的direct builds在离线图像缓存中运行良好,但生成的安装文件(使用Inno setup)在以下日志中崩溃:

Set property 'System.Windows.Controls.ItemsControl.ItemTemplate' threw an exception.
Stack Trace:    at System.Windows.Markup.WpfXamlLoader.Load(XamlReader xamlReader, IXamlObjectWriterFactory writerFactory, Boolean skipJournaledProperties, Object rootObject, XamlObjectWriterSettings settings, Uri baseUri)
   at System.Windows.Markup.WpfXamlLoader.LoadBaml(XamlReader xamlReader, Boolean skipJournaledProperties, Object rootObject, XamlAccessLevel accessLevel, Uri baseUri)
   at System.Windows.Markup.XamlReader.LoadBaml(Stream stream, ParserContext parserContext, Object parent, Boolean closeStream)
   at System.Windows.Application.LoadComponent(Object component, Uri resourceLocator)
   at MyApp.MyWindow.InitializeComponent() in E:\w_Development\DotNet\MyApp\MyWindow.xaml:line 1
   at MyApp.MyWindow..ctor(Window window) in E:\w_Development\DotNet\MyApp\MyWindow.xaml.cs:line 54
   at MyApp.MainWindow.<NavigateWithDelay>d__3.MoveNext() in E:\w_Development\DotNet\MyApp\MainWindow.xaml.cs:line 35
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.AsyncMethodBuilderCore.<>c.<ThrowAsync>b__6_0(Object state)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)
   at System.Windows.Threading.DispatcherOperation.InvokeImpl()
   at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state)
   at MS.Internal.CulturePreservingExecutionContext.CallbackWrapper(Object obj)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at MS.Internal.CulturePreservingExecutionContext.Run(CulturePreservingExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Windows.Threading.DispatcherOperation.Invoke()
   at System.Windows.Threading.Dispatcher.ProcessQueue()
   at System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)
   at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
   at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
   at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
   at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
   at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
   at System.Windows.Application.RunDispatcher(Object ignore)
   at System.Windows.Application.RunInternal(Window window)
   at System.Windows.Application.Run(Window window)
   at MyApp.App.Main()

我已经发了 an issue regarding this crash in library's issue-board .