protected override void Calculate()
{
if (textBox_FromUnit.Text != string.Empty)
{
LengthConverter lenthConverter = new LengthConverter(decimal.Parse(textBox_FromUnit.Text),
comboBox_FromUnit.Text.Replace(" ", "_"),
comboBox_ToUnit.Text.Replace(" ", "_"));
textBox_ToUnit.Text = lenthConverter.ConvertUnit().ToString();
}
}