public void OnPreviousButtonClick()
{
MWindow.Next.IsEnabled = true;
MWindow.Final.IsEnabled = true;
DrawObj.StepNumber = stepNumber - 1;
DrawObj.DrawPrevious(stepNumber);
stepNumber--;
if (stepNumber == 0)
{
MWindow.Previous.IsEnabled = false;
MWindow.Initial.IsEnabled = false;
}
MWindow.TextBoxStepNumber.Text = stepNumber.ToString();
}