我正在使用 MVVM 处理 WPF 应用程序。在 imageSlider 中加载和编辑图像会给我错误和异常。
加载图像：Insufficient memory to handle
编辑图像：Sharing violation
视图模型：
public class ImageList : INotifyPropertyChanged
{
#region Fields
private ObservableCollection<ImageItem> images = new ObservableCollection<ImageItem>();
private int selectedIndex;
private ImageItem currentImage;
#endregion Fields
#region Properties
public ObservableCollection<ImageItem> Images
{
get { return images; }
set { images = value; }
}
public int SelectedIndex
{
get { return selectedIndex; }
set
{
if(value < Images.Count && value > -1)
{
selectedIndex = value; OnPropertyChanged();
CurrentImage = Images[selectedIndex];
}
}
}
public ImageItem CurrentImage
{
get { return currentImage; }
set { currentImage = value; OnPropertyChanged(); }
}
#endregion Properties
#region Public Methods
public void Next()
{
SelectedIndex ++;
}
public void Back()
{
SelectedIndex--;
}
#endregion Public Methods
#region Methods
public void AddNewImage()
{
OpenFileDialog dlg = new OpenFileDialog();
dlg.Filter = "Image files (*.jpg, *.jpeg, *.jpe, *.gif, *.png, *.bmp, *.tif) | *.jpg; *.jpeg; *.jpe; *.gif; *.png, *.bmp, *.tif";
dlg.ShowDialog();
if(dlg.FileName != "")
{
Images.Add(new ImageItem() { URI = new Uri(dlg.FileName) });
SelectedIndex = Images.Count - 1;
}
}
#endregion Methods
#region Constructors
public ImageList()
{
_canExecute = true;
}
#endregion Constructors
#region Commands
private ICommand _clickCommand;
public ICommand ClickCommand
{
get
{
return _clickCommand ?? (_clickCommand = new CommandHandler(() => AddNewImage(), _canExecute));
}
}
private bool _canExecute;
private ICommand nextCommand;
public ICommand NextCommand
{
get
{
if (nextCommand == null)
{
nextCommand = new CommandHandler(()=> OnNextCommand(), true);
}
return nextCommand;
}
set { nextCommand = value; }
}
private void OnNextCommand()
{
Next();
}
private ICommand backCommand;
public ICommand BackCommand
{
get
{
if(backCommand == null)
{
backCommand = new CommandHandler(() => OnBackCommand(), true);
}
return backCommand;
}
set { backCommand = value; }
}
private void OnBackCommand()
{
Back();
}
private ICommand _clickCommand;
public ICommand ClickCommand
{
get
{
return _clickCommand ?? (_clickCommand = new CommandHandler(() => AddNewImage(), _canExecute));
}
}
private ICommand _EditImageCommand;
public ICommand EditImageCommand
{
get
{
return _EditImageCommand ?? (_EditImageCommand = new CommandHandler(obj => EditImage(obj), _canExecute));
}
}
#endregion Commands
public void EditImage(object obj)
{
string ss = ((ImageItem)obj).URI.AbsolutePath;
Process proc = Process.Start(ss);
if (proc != null)
{
proc.EnableRaisingEvents = true;
ProcessStartInfo startInfo = new ProcessStartInfo();
//startInfo.Verb = "edit";
startInfo.FileName = ("mspaint.exe");
proc.StartInfo = startInfo;
}
}
#region INotifyPropertyChanged
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
#endregion INotifyPropertyChanged
}`
模型：
public class ImageItem
{
public Uri URI { get; set; }
private BitmapSource _Source;
public BitmapSource Source
{
get
{
try
{
if (_Source == null) _Source = new BitmapImage(URI);//lazy loading
}
catch (Exception)
{
_Source = null;
}
return _Source;
}
}
public void Save(string filename)
{
var img = BitmapFrame.Create(Source);
var encoder = new JpegBitmapEncoder();
encoder.Frames.Add(img);
using (var saveStream = System.IO.File.OpenWrite(filename))
encoder.Save(saveStream);
}
}
XAML
<DockPanel>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*"></RowDefinition>
<RowDefinition Height="30"></RowDefinition>
<RowDefinition Height="200"></RowDefinition>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="30"></ColumnDefinition>
<ColumnDefinition Width="*"></ColumnDefinition>
<ColumnDefinition Width="30"></ColumnDefinition>
</Grid.ColumnDefinitions>
<Button Content="<" Command="{Binding BackCommand}" Width="25" Grid.Row="0" Grid.Column="0"/>
<Button DockPanel.Dock="Right" Content=">" Command="{Binding NextCommand}" Width="25" Grid.Row="0" Grid.Column="2"/>
<Image Source="{Binding CurrentImage.Source, Mode=OneWay}" Grid.Row="0" Grid.Column="1">
<Image.ContextMenu>
<ContextMenu>
<MenuItem Header="Edit Image" Command="{Binding EditImageCommand, Source={StaticResource SliderViewModel}}" CommandParameter="{Binding CurrentImage}"></MenuItem>
</ContextMenu>
</Image.ContextMenu>
</Image>
<Button Content="Add" Command="{Binding ClickCommand}" Height="30" Width="50" Grid.Row="1" Grid.Column="0" Grid.ColumnSpan="4"></Button>
<!--<Image Source="{Binding CurrentImage.Source, Mode=OneWay}" Grid.Row="2" Grid.Column="1"/>-->
</Grid>
</DockPanel>
上面的代码适用于 imageSlider（Next 和 Back）。但是在编辑过程中它会打开mspaint，当我保存它时会抛出我Sharing violation error。厌倦了在 SO here和here中发布的几个解决方案。尝试这些时，我可以编辑图像并保存而不会出现任何错误。但是当使用 Slider 控件（Next 和 Back）并加载较重的图像时，它经常会抛出Insufficient memory to handle异常。
所以现在我需要消除这两个问题。请帮忙。