<SerializableAttribute()>
Public Class WiaException 
   Inherits Leadtools.LeadtoolsException
   Implements _Exception, ISerializable 

Dim instance As WiaException

[SerializableAttribute()]
public class WiaException : Leadtools.LeadtoolsException, _Exception, ISerializable  

[SerializableAttribute()]
public ref class WiaException : public Leadtools.LeadtoolsException, _Exception, ISerializable  

<Test> _
Public Sub WiaExceptionExample(ByVal parent As IWin32Window)
   Dim wiaSession As WiaSession = Nothing
   Try
      If (Not WiaSession.IsAvailable(WiaVersion.Version1)) Then
         MessageBox.Show("WIA version 1.0 not installed.")
         Return
      End If

      ' initialize a new WIA wiaSession
      wiaSession = New WiaSession()
      wiaSession.Startup(WiaVersion.Version1)

      Dim res As DialogResult = wiaSession.SelectDeviceDlg(parent, WiaDeviceType.Default, WiaSelectSourceFlags.NoDefault)
      If res <> DialogResult.OK Then
         MessageBox.Show("Error selecting WIA device.")
         wiaSession.Shutdown()
         Return
      End If

      ' acquire a page, if paper jam, allow the user to retry
      Dim done As Boolean = False
      Do While Not done
         Try
            AddHandler wiaSession.AcquireEvent, AddressOf wiaSession_AcquireEvent2

            res = wiaSession.Acquire(parent, Nothing, WiaAcquireFlags.ShowUserInterface Or WiaAcquireFlags.UseCommonUI)
            MessageBox.Show("Success")
            done = True

            RemoveHandler wiaSession.AcquireEvent, AddressOf wiaSession_AcquireEvent2
         Catch ex As WiaException
            If ex.Code = WiaExceptionCode.PaperJam Then
               If MessageBox.Show("Paper jam.  Fix and retry?", "WIA", MessageBoxButtons.YesNo) = DialogResult.No Then
                  done = True
               End If
            Else
               ' other error, propagate
               Throw ex
            End If
         End Try
      Loop
   Catch ex As WiaException
      MessageBox.Show(String.Format("WIA error:{0}Code: {1}{0}Message: {2}", Environment.NewLine, ex.Code, ex.Message))
   Catch ex As Exception
      MessageBox.Show(String.Format("Other error: Message:{0}", ex.Message))
   Finally
      If Not wiaSession Is Nothing Then
         wiaSession.Shutdown()
      End If
   End Try
End Sub

Private Sub wiaSession_AcquireEvent2(ByVal sender As Object, ByVal e As WiaAcquireEventArgs)
   Application.DoEvents()

   If Not e.Image Is Nothing Then
      e.Image.Dispose()
   End If

   e.Cancel = False
End Sub

public void WiaExceptionExample(IWin32Window parent)
{
   WiaSession wiaSession = null;

   try
   {
      if (!WiaSession.IsAvailable(WiaVersion.Version1))
      {
         MessageBox.Show("WIA version 1.0 not installed.");
         return;
      }

      // initialize a new WIA wiaSession
      wiaSession = new WiaSession();
      wiaSession.Startup(WiaVersion.Version1);

      DialogResult res = wiaSession.SelectDeviceDlg(parent, WiaDeviceType.Default, WiaSelectSourceFlags.NoDefault);
      if (res != DialogResult.OK)
      {
         MessageBox.Show("Error selecting WIA device.");
         wiaSession.Shutdown();
         return;
      }

      // acquire a page, if paper jam, allow the user to retry
      bool done = false;
      while(!done)
      {
         try
         {
            wiaSession.AcquireEvent += new EventHandler<WiaAcquireEventArgs>(wiaSession_AcquireEvent2);

            res = wiaSession.Acquire(parent, null, WiaAcquireFlags.ShowUserInterface | WiaAcquireFlags.UseCommonUI);
            MessageBox.Show("Success");
            done = true;

            wiaSession.AcquireEvent -= new EventHandler<WiaAcquireEventArgs>(wiaSession_AcquireEvent2);
         }
         catch(WiaException ex)
         {
            if(ex.Code == WiaExceptionCode.PaperJam)
            {
               if(MessageBox.Show("Paper jam.  Fix and retry?", "WIA", MessageBoxButtons.YesNo) == DialogResult.No)
                  done = true;
            }
            else
            {
               // other error, propagate
               throw ex;
            }
         }
      }
   }
   catch(WiaException ex)
   {
      MessageBox.Show(string.Format("WIA error:{0}Code: {1}{0}Message: {2}", Environment.NewLine, ex.Code, ex.Message));
   }
   catch(Exception ex)
   {
      MessageBox.Show(string.Format("Other error: Message:{0}", ex.Message));
   }
   finally
   {
      if(wiaSession != null)
         wiaSession.Shutdown();
   }
}

void wiaSession_AcquireEvent2(object sender, WiaAcquireEventArgs e)
{
   Application.DoEvents();

   if (e.Image != null)
      e.Image.Dispose();

   e.Cancel = false;
}