private void BtnProccess_OnClick(object sender, RoutedEventArgs e) { int limit = 1; IDetectingAlgorithm algrorithm = (IDetectingAlgorithm)SelectedAlgorithm.SelectedItem; if (Limit.Text != "" && Int32.TryParse(Limit.Text, out limit) && algrorithm != null && this._source != null) { Bitmap bitmap = BitmapConverter.BitmapImage2Bitmap(this._source); Bitmap edges = algrorithm.DetecteEdges(bitmap, limit); BitmapImage imageEdges = BitmapConverter.Bitmap2ImageSource(edges); FilteredImage.Source = imageEdges; } else { MessageBox.Show( "Please input a limit for filtering. \nYou may not select file. \nYou have to select algorithm for filtering"); } }