protected override void Calculate()
 {
     if (textBox_FromUnit.Text != string.Empty)
     {
         WeightAndMassConverter weightAndMassConverter = new WeightAndMassConverter(decimal.Parse(textBox_FromUnit.Text), comboBox_FromUnit.Text, comboBox_ToUnit.Text);
         textBox_ToUnit.Text = weightAndMassConverter.ConvertUnit().ToString("0.##########");
     }
 }
        protected override void SetComboBox()
        {
            comboBox_FromUnit.DataSource    = new BindingSource(WeightAndMassConverter.NiceComboboxData(), null);
            comboBox_FromUnit.DisplayMember = "Key";
            comboBox_FromUnit.ValueMember   = "Value";

            comboBox_ToUnit.DataSource    = new BindingSource(WeightAndMassConverter.NiceComboboxData(), null);
            comboBox_ToUnit.DisplayMember = "Key";
            comboBox_ToUnit.ValueMember   = "Value";
        }