问题上采取WP图像和显示他们与MvvmCross

本文介绍了问题上采取WP图像和显示他们与MvvmCross的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！问题描述我要使用相机拍摄的照片，并显示它我在I want to take a photo with the camera and show it on the page I am at所以我有一个视图模型，我都拍摄照片，并显示它So I have a ViewModel where I both take the picture and show itpublic class CamViewModel : MvxViewModel, IMvxServiceConsumer<IInstalledMeter>, IMvxServiceConsumer<ICamaraService> { public CamViewModel() { this.GetService<ICamaraService>().PhotoSavedEvent += PhotoSaved; if (!String.IsNullOrEmpty(this.GetService<IInstalledMeter>().ImagePath)) { ImagePath = this.GetService<IInstalledMeter>().ImagePath; } TakePicture(); } private string _imagePath; public string ImagePath { get { return _imagePath; } set { _imagePath = value; FirePropertyChanged("ImagePath"); } } //Navigate back to InstallUnit public IMvxCommand OpenCamaraCommand { get { return new MvxRelayCommand(TakePicture); } } private void PhotoSaved(object sender, PhotoSavedResultEventArgs e) { ImagePath = e.ImagePath; } private void TakePicture() { this.GetService<ICamaraService>().TakePhoto(); }}这使用CameraService，无论拍摄照片并保存画面上的独立存储（我知道，不好的关注分离）This uses a CameraService that both takes the picture and saves the picture on isolated storage (I know, bad seperation of concern)public class CamaraService : IMvxServiceConsumer<IMvxPictureChooserTask>, IMvxServiceConsumer<IMvxSimpleFileStoreService>, IMvxServiceConsumer<IInstalledMeter>, ICamaraService{ private const int MaxPixelDimension = 1024; private const int DefaultJpegQuality = 70; public event EventHandler<PhotoSavedResultEventArgs> PhotoSavedEvent; private void PhotoTaken(PhotoSavedResultEventArgs e) { if (PhotoSavedEvent != null) { PhotoSavedEvent(this, e); } } public string ImagePath { get; set; } public void TakePicture() { this.GetService<IMvxPictureChooserTask>().TakePicture( MaxPixelDimension, DefaultJpegQuality, SavePicture, () => { /* cancel is ignored */ }); } public void TakePhoto() { TakePicture(); } public void SavePicture(Stream image) { var newImage = Save(image); if (newImage != "") { DeleteOldImage(this.GetService<IInstalledMeter>().ImagePath); this.GetService<IInstalledMeter>().ImagePath = newImage; PhotoTaken(new PhotoSavedResultEventArgs {ImagePath = newImage}); } } public void UpdateModel(string filename) { } public void DeleteOldImage(string fileName) { try { if (String.IsNullOrEmpty(fileName)) return; var fileService = this.GetService<IMvxSimpleFileStoreService>(); fileService.DeleteFile(fileName); } catch { } } public string Save(Stream stream) { try { var fileName = Guid.NewGuid().ToString(); var fileService = this.GetService<IMvxSimpleFileStoreService>(); fileName = Path.Combine("Image", fileName); fileService.WriteFile(fileName, stream.CopyTo); return fileName; } catch (ThreadAbortException) { throw; } catch (Exception exception) { return ""; } }} 在Windows Phone的视图显示图像The View on Windows Phone to display the image is<Views:BaseCamViewx:Class="UI.WP7.Views.InstallMeter.CamView"xmlns:Views="clr-namespace:UI.WP7.Views.InstallMeter"xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"xmlns:d="http://schemas.microsoft.com/expression/blend/2008"xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"xmlns:nativeConverters="clr-namespace:UI.WP7.NativeConverters"FontFamily="{StaticResource PhoneFontFamilyNormal}"FontSize="{StaticResource PhoneFontSizeNormal}"Foreground="{StaticResource PhoneForegroundBrush}"SupportedOrientations="Portrait" Orientation="Portrait"mc:Ignorable="d"shell:SystemTray.IsVisible="True"><Views:BaseCamView.Resources> <nativeConverters:PathToImageConverter x:Name="PathToImageConverter" /></Views:BaseCamView.Resources><Grid x:Name="LayoutRoot" Background="Transparent"> <Grid.RowDefinitions> <RowDefinition Height="Auto"/> <RowDefinition Height="*"/> </Grid.RowDefinitions>  <StackPanel Grid.Row="0" Margin="12,17,0,28"> <TextBlock Text="MY sdf" Style="{StaticResource PhoneTextNormalStyle}"/> <TextBlock Text="{Binding ImagePath}" Margin="9,-7,0,0" Style="{StaticResource PhoneTextTitle1Style}"/> </StackPanel> <Image Grid.Row="1" Source="{Binding ImagePath, Converter={StaticResource PathToImageConverter}}" Height="200" Width="700" Stretch="Uniform" /></Grid> 和这个视图使用一个转换器将路径转换为BitmapImage的And this view uses a converter to convert the path to a bitmapimage public class PathToImageConverter : IValueConverter, IMvxServiceConsumer<IMvxSimpleFileStoreService>{ public object Convert(object value, Type targetType, object parameter, CultureInfo culture) { byte[] contents = null; try { var file = this.GetService(); file.TryReadBinaryFile((string)value, out contents); } catch (Exception) { // masked } if (contents == null) return null; using (var stream = new MemoryStream(contents)) { var image = new BitmapImage(); image.SetSource(stream); return image; } } 不过，当过我尝试拍照此位在转炉返回null But when ever I try to take a picture this bit in the converter returns nullif (contents == null) return null; 所以我推测，这意味着图像不可访问/保存或文件名是错误的，但不知道当错误发生So I presume that means the image is not accessable / saved or the filename is wrong, but not sure where the error happens推荐答案我认为你需要单步调试和调试图片代码。I think you need to step through and debug the photo code.您也可以尝试加入一些跟踪的异常捕获处理You could also try adding some trace to the Exception catch handlers.一个猜测是，您的GUID基于文件名包含无效字符 - 见 HTTP：// MSDN。 microsoft.com/en-us/library/system.io.path.getinvalidpathchars%28v=vs.95%29.aspx 尝试 Guid.ToString（N）+.JPG 的略少错位的文件名One guess is that your GUID based file name includes invalid characters - see http://msdn.microsoft.com/en-us/library/system.io.path.getinvalidpathchars%28v=vs.95%29.aspx Try Guid.ToString("N") + ".jpg" for a slightly less mangled file name但你真的需要通过代码来跟踪并找出错误发生。But really you need to trace through the code and find out where the error is occurring. 这篇关于问题上采取WP图像和显示他们与MvvmCross的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！