Question

图像库WPF应用程序会发生这种情况，该应用程序使用xaml显示列表框中的缩略图和所选图像

问题 - 是否有办法安全删除当前选定的图像而不会收到IOException？

仅供参考 - 用户拥有该目录的所有权限，其他进程没有使用该文件

这是删除文件的代码

 void deleteCurrentlySelectedImageClick()
{
var o = SelectedPhoto; // class MyPhoto with a string FilePath
string path = o.FilePath;
// ViewList is of type List<MyPhoto> bound to listbox for displaying thumbnails            
// for the purists 
// it can/should be of type ObservableCollection<> 
// but this doesn't change that often here :)
ViewList.Remove(o);   
o = null;
firePropertyChanged("ViewList");
firePropertyChanged("SelectedPhoto");

FileInfo fi = new FileInfo(path);
fi.Delete();
}

例外是

System.IO.IOException was unhandled by user code
  HResult=-2147024864
  Message=The process cannot access the file 'C:\<path>\US-wp2.jpg' because it is being used by another process.
  Source=mscorlib
  StackTrace:
       at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
       at System.IO.FileInfo.Delete()

缩略图的XAML是

<ListBox 
   IsSynchronizedWithCurrentItem="True"
   Name="PhotosListBox" 
   Style="{StaticResource PhotoListBoxStyle}" 
   Margin="5" 
   SelectionMode="Extended" 
   ItemsSource="{Binding ViewList}" 
   SelectedIndex="0" 
   SelectionChanged="PhotosListBox_SelectionChanged"
   >

.... //资源xaml是......

    <DataTemplate DataType="{x:Type sample1:MyPhoto}">
        <Grid VerticalAlignment="Center" HorizontalAlignment="Center" Margin="6">
            <!-- Drop Shadow -->
            <Border HorizontalAlignment="Stretch" VerticalAlignment="Stretch" CornerRadius="4" Background="#44000000">
                <Border.RenderTransform>
                    <TranslateTransform X="5" Y="5" />
                </Border.RenderTransform>
                <Border.BitmapEffect>
                    <BlurBitmapEffect Radius="8" />
                </Border.BitmapEffect>
            </Border>
            <!-- Image Template -->
            <Border Padding="4" Background="White" BorderBrush="#22000000" BorderThickness="1">
                <StackPanel Orientation="Vertical">
                    <Image Source="{Binding FilePath}"/>
                </StackPanel>
            </Border>
        </Grid>
    </DataTemplate>

        <!-- Main photo catalog view -->
    <Style TargetType="{x:Type ListBox}" x:Key="PhotoListBoxStyle">
        <Setter Property="Foreground" Value="White" />
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type ListBox}" >
                    <WrapPanel Margin="5" IsItemsHost="True" Orientation="Horizontal" 
                   ItemHeight="{Binding ElementName=ZoomSlider, Path='Value'}" 
                   ItemWidth="{Binding ElementName=ZoomSlider, Path='Value'}" 
                   VerticalAlignment="Top" HorizontalAlignment="Stretch" />
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

    <!-- Style for an individual generic item -->
    <Style TargetType="{x:Type ListBoxItem}">
        <Setter Property="Background" Value="Transparent" />
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type ListBoxItem}" >
                    <Border SnapsToDevicePixels="True" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Background="{TemplateBinding Background}">
                        <ContentPresenter />
                    </Border>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsSelected" Value="True">
                            <Setter Property="Background" Value="#445B6249"   />
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

全尺寸图片xaml只是

 <Image Source="{Binding SelectedPhoto.FilePath}" HorizontalAlignment="Center" VerticalAlignment="Center" />

Answer 1

您的问题的答案是：不，没有安全的删除文件的方法，您需要处理IOException。可能有多种原因，例如：

您可能没有删除文件的访问权限
该文件由另一个进程使用（某人/其他人打开该文件）
该文件已被删除且不存在

在您的具体情况下，请检查此问题：Problems overwriting (re-saving) image when it was set as image source

Answer 2

您应该关闭/处置图像的原始文件流。加载时将它们复制到MemoryStrean。

Answer 3

    public static bool Delete(FileInfo fi)
    {
        int retries = 40;
        bool ret = false;
        SpinWait _sw = new SpinWait();

        while (!ret && retries-- > 0)
        {
            if (fi?.Exists ?? false)
            {
                fi.IsReadOnly = false;
                try
                {
                    fi.Delete();
                    ret = true;
                }
                catch (IOException) { _sw.SpinOnce(); }
            }
            else break;
        }
        return ret;
    }

如果需要说明，将进行编辑。

FileInfo.Delete中的异常 - IOException

3 个答案: