Use SelectionChanged event in two textbox , one depend from the other

Question

I have two Textbox and I'm trying to add SelectionChanged Event to the two textbox :

TextBox A => Amount
TextBox B => Summary

The scenario is like :

Two Textbox are empty:

The user enter the amount the summary will be equals to 100 * Amount

The user enter the summary after clear the field of amount , he should get summary / 100 in the textbox of amount

 private void Amount_SelectionChanged(object sender, RoutedEventArgs e)
  {
      if (!string.IsNullOrEmpty(Amount.Text.ToString()))
      {
          Summary.IsReadOnly = true;
          Summary.Text = (ToDecimalValue(Amount.Text) * 100).ToString();
          Amount.IsReadOnly = false;

      }
      else
      {
          Summary.Text = "";
          Summary.IsReadOnly = false;
      }


  }

  private void Summary_SelectionChanged(object sender, RoutedEventArgs e)
  {
      if (!string.IsNullOrEmpty(Summary.Text.ToString()))
      {
          Amount.IsReadOnly = true;
          Amount.Text = (ToDecimalValue(Summary.Text) / 100).ToString()
          Summary.IsReadOnly = false;

      }
      else
      {
          Summary.Text = "";
          Summary.IsReadOnly = false;
      }

  }

How can I do this?

score 1 · Accepted Answer · answered Sep 30 '21 at 14:26

I believe there is a simple solution:

private bool _isEditing;

private void Amount_TextChanged(object _, RoutedEventArgs __)
{
    if (_isEditing)
        return;

    _isEditing = true;

    if (double.TryParse(Amount.Text, out double amount)
        Summary.Text = (amount * 100).ToString();
    else
        Summary.Clear();

    _isEditing = false;
}

private void Summary_TextChanged(object _, RoutedEventArgs __)
{
    if (_isEditing)
        return;

    _isEditing = true;

    if (double.TryParse(Summary.Text, out double summary)
        Amount.Text = (summary / 100).ToString();
    else
        Amount.Clear();

    _isEditing = false;
}

Notes:

I changed "SelectionChanged" to "TextChanged", as it is the event you want to watch if the user changes the value in the TextBox.
I replaced ToDecimalValue() by double.TryParse(), but this will work only if the decimal separator matches that of the application's current culture.
_ and __ mean that the parameters are not used.
If you want the TextBox to only accepts numbers, see this question.

Yes , I have tested your solution and it worke , thank you. – abdou31 Sep 30 '21 at 14:35 — abdou31, Sep 30 '21 at 14:35

Use SelectionChanged event in two textbox , one depend from the other

1 Answers1