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Working with image streams and files in Silverlight

For security and other reasons, Silverlight offers no direct access to the operating system's file system. Even so, there are still several ways to interact with files, whether they are on disk, in memory, over the web, in databases--virtually any location where images are stored. The following snippets show various ways to load/save images with LEADTOOLS Silverlight.

  1. Using the Microsoft Load and Save Dialogs:

    [Visual Basic]

                'Loading
            Try
              Dim codecs As RasterCodecs = New RasterCodecs()
              Dim ofd As OpenFileDialog = New OpenFileDialog()
              If ofd.ShowDialog() = True Then
                 Dim fileStream As FileStream = ofd.File.OpenRead()
                 Try
                    viewerControl.Image = codecs.Load(fileStream)
                 Finally
                    fileStream.Dispose()
                 End Try
              End If
            Catch ex As RasterException
              ' See if LEADTOOLS could not recognize this image format
              If ex.Code = RasterExceptionCode.FileFormat Then
                 MessageBox.Show("File does not contain an image format recognizable by LEADTOOLS")
              Else
                 ' Other LEADTOOLS error (file might be corrupted, read error, etc)
                 MessageBox.Show(String.Format("Error loading file.{0}Leadtools code: {1}{0}Message: {2}", Environment.NewLine, ex.Code, ex.Message))
              End If
            Catch ex As Exception
              ' Other errors
              MessageBox.Show(String.Format("Error loading file.{0}{1}", Environment.NewLine, ex.Message))
            End Try
            'Saving 
            Try
              Dim codecs As RasterCodecs = New RasterCodecs()
              Dim sfd As SaveFileDialog = New SaveFileDialog()
              If sfd.ShowDialog() = True Then
                 Dim stream As Stream = sfd.OpenFile()
                 Try
                    codecs.Save(viewerControl.Image, stream, Leadtools.RasterImageFormat.Jpeg, 0)
                 Finally
                    stream.Dispose()
                 End Try
              End If
            Catch ex As RasterException
              ' Other LEADTOOLS error (file might be corrupted, read error, etc)
              MessageBox.Show(String.Format("Error saving file.{0}Leadtools code: {1}{0}Message: {2}", Environment.NewLine, ex.Code, ex.Message))
            Catch ex As Exception
              ' Other errors
              MessageBox.Show(String.Format("Error saving file.{0}{1}", Environment.NewLine, ex.Message))
            End Try

    [C#]

                //Loading
            try
            {
              RasterCodecs codecs = new RasterCodecs();
              OpenFileDialog ofd = new OpenFileDialog();
              if (ofd.ShowDialog() == true)
              {
                 using (FileStream fileStream = ofd.File.OpenRead())
                    viewerControl.Image = codecs.Load(fileStream);
              }
            }
            catch (RasterException ex)
            {
              // See if LEADTOOLS could not recognize this image format
              if (ex.Code == RasterExceptionCode.FileFormat)
                 MessageBox.Show("File does not contain an image format recognizable by LEADTOOLS");
              else
              {
                 // Other LEADTOOLS error (file might be corrupted, read error, etc)
                 MessageBox.Show(string.Format("Error loading file.{0}Leadtools code: {1}{0}Message: {2}", Environment.NewLine, ex.Code, ex.Message));
              }
            }
            catch (Exception ex)
            {
              // Other errors
              MessageBox.Show(string.Format("Error loading file.{0}{1}", Environment.NewLine, ex.Message));
            }
            //Saving
            try
            {
              RasterCodecs codecs = new RasterCodecs();
              using (IsolatedStorageFile store = IsolatedStorageFile.GetUserStoreForApplication())
              using (IsolatedStorageFileStream stream = store.CreateFile("myfile.jpg"))
                 codecs.Save(viewerControl.Image, stream, Leadtools.RasterImageFormat.Jpeg, 0);
            }
            catch (RasterException ex)
            {
              // Other LEADTOOLS error (file might be corrupted, read error, etc)
              MessageBox.Show(string.Format("Error saving file.{0}Leadtools code: {1}{0}Message: {2}", Environment.NewLine, ex.Code, ex.Message));
            }
            catch (Exception ex)
            {
              // Other errors
              MessageBox.Show(string.Format("Error saving file.{0}{1}", Environment.NewLine, ex.Message));
            }

  2. Using the Silverlight Isolated Storage System:

    [Visual Basic]

                'Loading
            Try
              Dim codecs As RasterCodecs = New RasterCodecs()
              Dim store As IsolatedStorageFile = IsolatedStorageFile.GetUserStoreForApplication()
              Dim stream As IsolatedStorageFileStream = store.OpenFile("myfile.jpg", FileMode.Open, FileAccess.Read)
              Try
                 viewerControl.Image = codecs.Load(stream)
              Finally
                 store.Dispose()
                 stream.Dispose()
              End Try
            Catch ex As RasterException
              ' See if LEADTOOLS could not recognize this image format
              If ex.Code = RasterExceptionCode.FileFormat Then
                 MessageBox.Show("File does not contain an image format recognizable by LEADTOOLS")
              Else
                 ' Other LEADTOOLS error (file might be corrupted, read error, etc)
                 MessageBox.Show(String.Format("Error loading file.{0}Leadtools code: {1}{0}Message: {2}", Environment.NewLine, ex.Code, ex.Message))
              End If
            Catch ex As Exception
              ' Other errors
              MessageBox.Show(String.Format("Error loading file.{0}{1}", Environment.NewLine, ex.Message))
            End Try         
            'Saving
            Try
              Dim codecs As RasterCodecs = New RasterCodecs()
              Dim store As IsolatedStorageFile = IsolatedStorageFile.GetUserStoreForApplication()
              Dim stream As IsolatedStorageFileStream = store.CreateFile("myfile.jpg")
              Try
                 codecs.Save(viewerControl.Image, stream, Leadtools.RasterImageFormat.Jpeg, 0)
              Finally
                 store.Dispose()
                 stream.Dispose()
              End Try
            Catch ex As RasterException
              ' Other LEADTOOLS error (file might be corrupted, read error, etc)
              MessageBox.Show(String.Format("Error saving file.{0}Leadtools code: {1}{0}Message: {2}", Environment.NewLine, ex.Code, ex.Message))
            Catch ex As Exception
              ' Other errors
              MessageBox.Show(String.Format("Error saving file.{0}{1}", Environment.NewLine, ex.Message))
            End Try

    [C#]

                //Loading
            try
            {
              RasterCodecs codecs = new RasterCodecs();
              using (IsolatedStorageFile store = IsolatedStorageFile.GetUserStoreForApplication())
              using (IsolatedStorageFileStream stream = store.OpenFile("myfile.jpg", FileMode.Open, FileAccess.Read))
                 viewerControl.Image = codecs.Load(stream);
            }
            catch (RasterException ex)
            {
              // See if LEADTOOLS could not recognize this image format
              if (ex.Code == RasterExceptionCode.FileFormat)
                 MessageBox.Show("File does not contain an image format recognizable by LEADTOOLS");
              else
              {
                 // Other LEADTOOLS error (file might be corrupted, read error, etc)
                 MessageBox.Show(string.Format("Error loading file.{0}Leadtools code: {1}{0}Message: {2}", Environment.NewLine, ex.Code, ex.Message));
              }
            }
            catch (Exception ex)
            {
              // Other errors
              MessageBox.Show(string.Format("Error loading file.{0}{1}", Environment.NewLine, ex.Message));
            }
            //Saving 
            try
            {
              RasterCodecs codecs = new RasterCodecs();
              SaveFileDialog sfd = new SaveFileDialog();
              if (sfd.ShowDialog() == true)
              {
                 using (Stream stream = sfd.OpenFile())
                    codecs.Save(viewerControl.Image, stream, Leadtools.RasterImageFormat.Jpeg, 0);
              }
            }
            catch (RasterException ex)
            {
              // Other LEADTOOLS error (file might be corrupted, read error, etc)
              MessageBox.Show(string.Format("Error saving file.{0}Leadtools code: {1}{0}Message: {2}", Environment.NewLine, ex.Code, ex.Message));
            }
            catch (Exception ex)
            {
              // Other errors
              MessageBox.Show(string.Format("Error saving file.{0}{1}", Environment.NewLine, ex.Message));
            }

  3. Using the WebClient Class to download images:

    [Visual Basic]

                ' You may need a cross domain policy file on the server containing the image in order to use the WebClient Class.
            Dim fileDownloader As WebClient = New WebClient()
            AddHandler fileDownloader.OpenReadCompleted, AddressOf fileDownloader_OpenReadCompleted
            fileDownloader.OpenReadAsync(New Uri("http://demo.leadtools.com/images/cmp/image1.cmp"), Nothing)
            Private Sub fileDownloader_OpenReadCompleted(ByVal sender As Object, ByVal e As OpenReadCompletedEventArgs)
              Try
                 Dim codecs As RasterCodecs = New RasterCodecs()
                    viewerControl.Image = codecs.Load(e.Result)
              Catch ex As RasterException
                 ' See if LEADTOOLS could not recognize this image format
                 If ex.Code = RasterExceptionCode.FileFormat Then
                    MessageBox.Show("File does not contain an image format recognizable by LEADTOOLS")
                 Else
                    ' Other LEADTOOLS error (file might be corrupted, read error, etc)
                    MessageBox.Show(String.Format("Error loading file.{0}Leadtools code: {1}{0}Message: {2}", Environment.NewLine, ex.Code, ex.Message))
                 End If
              Catch ex As Exception
                 ' Other errors
                 MessageBox.Show(String.Format("Error loading file.{0}{1}", Environment.NewLine, ex.Message))
              End Try
            End Sub

    [C#]

                // You may need a cross domain policy file on the server containing the image in order to use the WebClient Class.
            WebClient fileDownloader = new WebClient();
            fileDownloader.OpenReadCompleted += new OpenReadCompletedEventHandler(fileDownloader_OpenReadCompleted);
            fileDownloader.OpenReadAsync(new Uri("http://demo.leadtools.com/images/cmp/image1.cmp"), null);
            void fileDownloader_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
            {
              try
              {
                 RasterCodecs codecs = new RasterCodecs();
                 viewerControl.Image = codecs.Load(e.Result);
              }
              catch (RasterException ex)
              {
                 // See if LEADTOOLS could not recognize this image format
                 if (ex.Code == RasterExceptionCode.FileFormat)
                    MessageBox.Show("File does not contain an image format recognizable by LEADTOOLS");
                 else
                 {
                    // Other LEADTOOLS error (file might be corrupted, read error, etc)
                    MessageBox.Show(string.Format("Error loading file.{0}Leadtools code: {1}{0}Message: {2}", Environment.NewLine, ex.Code, ex.Message));
                 }
              }
              catch (Exception ex)
              {
                 // Other errors
                 MessageBox.Show(string.Format("Error loading file.{0}{1}", Environment.NewLine, ex.Message));
              }
            }

  4. Using a WCF or standard web service:

    [Visual Basic]

                'This is the completed event when calling the LEADTOOLS RasterService WCF Service. 
            'LEADTOOLS WCF Services can be used for loading files that the Silverlight library 
            'does not support, for writing barcodes, and much more. Please see Loading And Displaying An Image Using WCF In Silverlight for the complete tutorial.
            Private Sub client_ConvertCompleted(ByVal sender As Object, ByVal e As ConvertCompletedEventArgs)
              Try
                 If TypeOf e.Result Is ConvertResponse Then
                    Dim convertResponse As ConvertResponse = CType(IIf(TypeOf e.Result Is ConvertResponse, e.Result, Nothing), ConvertResponse)
                    'Image has been sent back from the service.
                    'Load the image into the viewer.
                    If TypeOf convertResponse.Destination Is RawBinaryData Then
                       Dim ms As MemoryStream = New MemoryStream((CType(IIf(TypeOf convertResponse.Destination Is RawBinaryData, convertResponse.Destination, Nothing), RawBinaryData)).Data)
                       Try
                           viewerControl.Image = codecs.Load(ms)
                       Finally
                          ms.Dispose()
                       End Try
                    End If
                 End If
              Catch ex As RasterException
                 ' See if LEADTOOLS could not recognize this image format
                 If ex.Code = RasterExceptionCode.FileFormat Then
                    MessageBox.Show("File does not contain an image format recognizable by LEADTOOLS")
                 Else
                    ' Other LEADTOOLS error (file might be corrupted, read error, etc)
                    MessageBox.Show(String.Format("Error loading file.{0}Leadtools code: {1}{0}Message: {2}", Environment.NewLine, ex.Code, ex.Message))
                 End If
              Catch ex As Exception
                 ' Other errors
                 MessageBox.Show(String.Format("Error loading file.{0}{1}", Environment.NewLine, ex.Message))
              End Try
            End Sub

    [C#]

                //This is the completed event when calling the LEADTOOLS RasterService WCF Service. 
            //LEADTOOLS WCF Services can be used for loading files that the Silverlight library 
            //does not support, for writing barcodes, and much more. Please see Loading And Displaying An Image Using WCF In Silverlight for the complete tutorial.
            void client_ConvertCompleted(object sender, ConvertCompletedEventArgs e)
            {
              try
              {
                 if (e.Result is ConvertResponse)
                 {
                    ConvertResponse convertResponse = e.Result as ConvertResponse;
                    //Image has been sent back from the service.
                    //Load the image into the viewer.
                    if (convertResponse.Destination is RawBinaryData)
                    {
                       using (MemoryStream ms = new MemoryStream((convertResponse.Destination as RawBinaryData).Data))
                          viewerControl.Image = codecs.Load(ms);
                    }
                 }
              }
              catch (RasterException ex)
              {
                 // See if LEADTOOLS could not recognize this image format
                 if (ex.Code == RasterExceptionCode.FileFormat)
                    MessageBox.Show("File does not contain an image format recognizable by LEADTOOLS");
                 else
                 {
                    // Other LEADTOOLS error (file might be corrupted, read error, etc)
                    MessageBox.Show(string.Format("Error loading file.{0}Leadtools code: {1}{0}Message: {2}", Environment.NewLine, ex.Code, ex.Message));
                 }
              }
              catch (Exception ex)
              {
                 // Other errors
                 MessageBox.Show(string.Format("Error loading file.{0}{1}", Environment.NewLine, ex.Message));
              }
            }