title: Entering Values into NumericUpDown with unit
body: <p>I have declared a control deriving from NumericUpDown to display a unit in the text area:</p>
  
  <pre><code>    public class NumericUpDownUnit : NumericUpDown
  {
      public string Unit { get; set; } = "";
      protected override void UpdateEditText()
      {
          Text = Value.ToString("N" + DecimalPlaces) + " " + Unit;
      }
  }
  </code></pre>
  
  <p>It works fine, but when I try to edit that value (e. g. "250 kg") as the application is running, it won't take it before I remove the unit from the text, because of course it's not a valid number.</p>
  
  <p>How can I extend my control to take the new value?</p>