Public Sub UseAsync() 

Dim instance As RasterCodecs
 
instance.UseAsync()

public void UseAsync()

public:
void UseAsync(); 

Public Sub UseAsyncExample()
      Dim srcFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp")
      Dim uri As New Uri(srcFileName)

      Dim codecs As New RasterCodecs()

      ' The RasterCodecs.AsyncWebClient is Nothing first
      Debug.Assert(Not IsNothing(codecs.AsyncWebClient))

      ' Force the RasterCodecs object to create it
      codecs.UseAsync()

      ' Change the Cache policy
      codecs.AsyncWebClient.CachePolicy = New System.Net.Cache.RequestCachePolicy(System.Net.Cache.RequestCacheLevel.CacheOnly)

      ' Now Load the file asynchronously
      AddHandler codecs.LoadAsyncCompleted, AddressOf useAsyncExample_LoadAsyncCompleted
      Dim image As RasterImage = codecs.LoadAsync(uri, Nothing)
   End Sub

   Private Sub useAsyncExample_LoadAsyncCompleted(ByVal sender As Object, ByVal e As CodecsLoadAsyncCompletedEventArgs)
      If e.Cancelled Then
         Console.WriteLine("User canceled")
      ElseIf Not IsNothing(e.Error) Then
         Console.WriteLine("Error: " + e.Error.Message)
      Else
         ' Get the image
         Dim image As RasterImage = e.Image
         Console.WriteLine("Image loaded asynchronously: Size = {0} by {1}", image.Width, image.Height)
         image.Dispose()
      End If

      ' Unsubscribe to the event and dispose the RasterCodecs object
      Dim codecs As RasterCodecs = DirectCast(sender, RasterCodecs)
      RemoveHandler codecs.LoadAsyncCompleted, AddressOf useAsyncExample_LoadAsyncCompleted
      codecs.Dispose()
   End Sub

Public NotInheritable Class LEAD_VARS
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"
End Class

public void UseAsyncExample()
   {
      string srcFileName = Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp");
      Uri uri = new Uri(srcFileName);

      RasterCodecs codecs = new RasterCodecs();

      // The RasterCodecs.AsyncWebClient is null first
      Debug.Assert(codecs.AsyncWebClient == null);

      // Force the RasterCodecs object to create it
      codecs.UseAsync();

      // Change the Cache policy
      codecs.AsyncWebClient.CachePolicy = new System.Net.Cache.RequestCachePolicy(System.Net.Cache.RequestCacheLevel.CacheOnly);

      // Now Load the file asynchronously
      codecs.LoadAsyncCompleted += new EventHandler<CodecsLoadAsyncCompletedEventArgs>(useAsyncExample_LoadAsyncCompleted);
      RasterImage image = codecs.LoadAsync(uri, null);
   }

   private void useAsyncExample_LoadAsyncCompleted(object sender, CodecsLoadAsyncCompletedEventArgs e)
   {
      if(e.Cancelled)
      {
         Console.WriteLine("User canceled");
      }
      else if(e.Error != null)
      {
         Console.WriteLine("Error: " + e.Error.Message);
      }
      else
      {
         // Get the image
         RasterImage image = e.Image;
         Console.WriteLine("Image loaded asynchronously: Size = {0} by {1}", image.Width, image.Height);
         image.Dispose();
      }

      // Unsubscribe to the event and dispose the RasterCodecs object
      RasterCodecs codecs = sender as RasterCodecs;
      codecs.LoadAsyncCompleted -= new EventHandler<CodecsLoadAsyncCompletedEventArgs>(useAsyncExample_LoadAsyncCompleted);
      codecs.Dispose();
   }

static class LEAD_VARS
{
   public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images";
}