private void Undo() { if (currentId > 0) { //BtnRedo.IsEnabled = true; ImageBrush myBrush = new ImageBrush(); string packUri = "pack://application:,,,/Wpf;component/Images/BtnRedo.png"; myBrush.ImageSource = new ImageSourceConverter().ConvertFromString(packUri) as ImageSource; BtnRedo.Background = myBrush; currentId--; myCanvas.Children.Clear(); Model model = new Model(); model = (Model)model.DeepClone(dataSaver.LoadData("c:/log/" + currentId.ToString())); dataObject = model; ShowInCanvas(dataObject); if (currentId == 0) { myBrush = new ImageBrush(); packUri = "pack://application:,,,/Wpf;component/Images/BtnUndoNotActive.png"; myBrush.ImageSource = new ImageSourceConverter().ConvertFromString(packUri) as ImageSource; BtnUndo.Background = myBrush; } } else { ImageBrush myBrush = new ImageBrush(); string packUri = "pack://application:,,,/Wpf;component/Images/BtnUndoNotActive.png"; myBrush.ImageSource = new ImageSourceConverter().ConvertFromString(packUri) as ImageSource; BtnUndo.Background = myBrush; } }