Exception in FileInfo.Delete - IOException

Question

This is happening for a image gallery WPF application which shows the thumbnails in a listbox and the selected image using xaml

Question - Is there a way to delete the currently selected image safely without getting the IOException ?

FYI - the user has ALL rights to the directory, no other process is using the file

here's the code to delete the file

 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();
}

the exception is

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()

the XAML for thumbnails is

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

.... // resources xaml is ....

    <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>

The full-size image xaml is simply

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

score 2 · Accepted Answer · edited May 23 '17 at 11:54

2

The answer to your question is: no, there's no safe way of deleting a file and you need to handle IOException. There may be multiple reasons, e.g.:

you may not have access rights to delete the file
the file is used by another process (someone/something else opened the file)
the file has already been deleted and doesn't exist

In your specific case, check this question: Problems overwriting (re-saving) image when it was set as image source

edited May 23 '17 at 11:54

Community

1
1

answered Nov 10 '13 at 00:54

Szymon

42,577
16
96
114

thanks, updated the Question above, in short, the user is admin, no other process is using the file, the FILE exists and is currently displayed in a thumbnail and another image control – Kumar Nov 10 '13 at 00:57

score 1 · Answer 2 · answered Nov 10 '13 at 01:00

1

You should close/dispose the original file stream of the image. Copy them to a MemoryStrean when loading.

answered Nov 10 '13 at 01:00

atomaras

2,468
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the binding is done using metaphor, so there's no MemoryStream to dispose of – Kumar Nov 10 '13 at 01:02
Kumar i'd change the metaphor. Bind to the actual memorystream replica of the photo instead of keeping the file handle open. – atomaras Nov 10 '13 at 20:59

ergohack · Answer 3 · 2017-10-16T20:12:09.533

    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;
    }

Will edit if explanation is needed.

Exception in FileInfo.Delete - IOException

3 Answers3