图像编辑例外

对于编辑器和查看器，您需要做一些不同的事情

您的模型需要更新为ViewModel，因为它将发生变化（您可以使用该模型来构建ViewModel，但是在这种情况下，模型中的功能太少，您还可以使用FIleInfo类作为您的模型）

public class ImageEditor: IDisposable,INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;
    private List<FileInfo> images = new List<FileInfo>();
    private FileInfo _ImageFile;
    public static readonly PropertyChangedEventArgs FilenameProperty = new PropertyChangedEventArgs(nameof(ImageFile));
    public FileInfo ImageFile
    {
        get { return _ImageFile; }
        set
        {
            _ImageFile = value;
            Strokes.Clear();
            PropertyChanged?.Invoke(this, ImageFrameProperty);
        }
    }
    private int selectedIndex;
    public static readonly PropertyChangedEventArgs SelectedIndexProperty = new PropertyChangedEventArgs(nameof(SelectedIndex));
    public int SelectedIndex
    {
        get { return selectedIndex; }
        private set
        {
            if (value < images.Count && value > -1)
            {
                selectedIndex = value;
                PropertyChanged?.Invoke(this, SelectedIndexProperty);
                ImageFile = images[selectedIndex];
                Load();
            }
        }
    }
    MemoryStream mem;
    private BitmapSource _ImageFrame;
    public static readonly PropertyChangedEventArgs ImageFrameProperty = new PropertyChangedEventArgs(nameof(ImageFrame));
    public BitmapSource ImageFrame
    {
        get { return _ImageFrame; }
        set
        {
            _ImageFrame = value;
            PropertyChanged?.Invoke(this, ImageFrameProperty);
        }
    }
    public StrokeCollection Strokes { get;  } = new StrokeCollection();
    public void Open(FileInfo file)
    {
        images.Add(file);
        SelectedIndex = images.Count - 1;
    }
    public void Next()
    {
        SelectedIndex++;
    }
    public void Back()
    {
        SelectedIndex--;
    }
    public void Load()
    {
        ImageFile.Refresh();
        if (ImageFile.Exists)
        {
            if (mem != null)
            {
                mem.Dispose();
            }
            using (var stream = ImageFile.OpenRead())
            {
                mem = new MemoryStream();
                stream.CopyTo(mem);
            }
            ImageFrame = BitmapFrame.Create(mem);
        }
    }
    public void Dispose()
    {
        if (mem != null)
        {
            mem.Dispose();
        }
        ImageFrame = null;
    }
    public void Save()
    {
        DrawingVisual drawingVisual = new DrawingVisual();
        using (DrawingContext drawingContext = drawingVisual.RenderOpen())
        {
            drawingContext.DrawImage(ImageFrame, new Rect(0, 0, ImageFrame.Width, ImageFrame.Height));
            foreach (var item in Strokes)
            {
                item.Draw(drawingContext);
            }
            drawingContext.Close();
            Strokes.Clear();
            var width = ImageFrame.Width;
            var height = ImageFrame.Height;
            var bitmap = new RenderTargetBitmap((int)width, (int)height, 96, 96, PixelFormats.Pbgra32);
            bitmap.Render(drawingVisual);
            ImageFrame = bitmap;
            var encoder = new PngBitmapEncoder();
            encoder.Frames.Add(BitmapFrame.Create(ImageFrame));
            using (var stream = ImageFile.OpenWrite())
            {
                encoder.Save(stream);
            }
        }
    }
}

注意：由于我们使用的是没有using语句的内存流，因此使用IDisposable接口清理是个好主意

它所做的是创建一个驻留在内存中的位图，然后将其用作帧，这将删除使用URI 的普通位图所获得的文件上的openRead锁定

接下来我们有编辑器本身

<Window x:Class="ImageDemo.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:ImageDemo"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525" Closing="Window_Closing" >
    <Window.DataContext>
        <local:ImageEditor x:Name="editor" />
    </Window.DataContext>
    <DockPanel>
        <Menu DockPanel.Dock="Top" >
            <MenuItem Header="File" >
                <MenuItem Command="ApplicationCommands.Open" />
                <MenuItem Command="ApplicationCommands.Save" />
            </MenuItem>
            <MenuItem Command="ApplicationCommands.Undo" />
            <ComboBox SelectedValue="{Binding DefaultDrawingAttributes.Color, ElementName=inkCanvas}">
                <Color>White</Color>
                <Color>Black</Color>
                <Color>Yellow</Color>
                <Color>Red</Color>
                <Color>Cyan</Color>
                <Color>SpringGreen</Color>
                <ComboBox.ItemTemplate>
                    <DataTemplate>
                        <Rectangle Width="15" Height="15">
                            <Rectangle.Fill>
                                <SolidColorBrush Color="{Binding Mode=OneWay}" />
                            </Rectangle.Fill>
                        </Rectangle>
                    </DataTemplate>
                </ComboBox.ItemTemplate>
            </ComboBox>
        </Menu>
        <Button Content="&lt;" Click="Back_Click"/>
        <Button Content="&gt;" DockPanel.Dock="Right" Click="Next_Click"/>
        <Grid HorizontalAlignment="Left" VerticalAlignment="Top" ScrollViewer.HorizontalScrollBarVisibility="Auto" ScrollViewer.VerticalScrollBarVisibility="Auto">
                <Image Source="{Binding ImageFrame}" Stretch="None"/>
                <InkCanvas x:Name="inkCanvas" Background="Transparent" Strokes="{Binding Strokes}" >
                    <InkCanvas.DefaultDrawingAttributes>
                        <DrawingAttributes x:Name="DrawSetting" />
                    </InkCanvas.DefaultDrawingAttributes>
                </InkCanvas>
            </Grid>
    </DockPanel>
</Window>
public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        CommandBindings.Add(new CommandBinding(ApplicationCommands.Save, execSave, hasChanged));
        CommandBindings.Add(new CommandBinding(ApplicationCommands.Open, execOpen));
        CommandBindings.Add(new CommandBinding(ApplicationCommands.Undo, execUndo, hasChanged));
    }
    private void execOpen(object sender, ExecutedRoutedEventArgs e)
    {
        OpenFileDialog dlg = new OpenFileDialog();
        if(dlg.ShowDialog() ?? false)
        {
            editor.Open(new System.IO.FileInfo(dlg.FileName));
        }
        e.Handled = true;
    }
    private void hasChanged(object sender, CanExecuteRoutedEventArgs e)
    {
        e.CanExecute = editor.Strokes.Count > 0;
        e.Handled = true;
    }
    private void execUndo(object sender, ExecutedRoutedEventArgs e)
    {
        editor.Strokes.Remove(editor.Strokes.Last());
        e.Handled = true;
    }
    private void execSave(object sender, ExecutedRoutedEventArgs e)
    {
        editor.Save();
        e.Handled = true;
    }
    private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
    {
        editor.Dispose();
    }
    private void Next_Click(object sender, RoutedEventArgs e)
    {
        editor.Next();
    }
    private void Back_Click(object sender, RoutedEventArgs e)
    {
        editor.Back();
    }
}

请注意，如果您正在对图像进行任何缩放/拉伸，则需要在渲染笔划之前反转笔划上的操作，或者编辑将与屏幕而非图像有关