Question

I have a string that is saved to a database that is compiled by two textboxes and separated by . e.g. if one TextBox has 2 and the other has 5, 2.5 gets saved to the database.

The issue I have now is with loading saved answers. Is there anyway to bind TextBox.Text to just a certain character of a string (i.e. the first textbox will always be SavedAnswer[0] and the other will be SavedAnswer[2]) or will I have to create a converter, pass in the full answer and then parse it?

Answer 1

There are a couple ways you could go about it. The easiest way would be to make your model have two related properties that you bind to separately. The important part is to make sure that they have their PropertyChanged events fired so the Binding works properly on the UI to reflect changes.

Example:

public class MyModel : INotifyPropertyChanged
{
  string fullAnswer;

  public event PropertyChangedEventHandler PropertyChanged;

  public string FullAnswer
  {
    get { return fullAnswer; }
    set
    {
      if(string.Equals(value, fullAnswer)) return; // skip for equal values

      fullAnswer = value;
      OnPropertyChanged("FullAnswer");
      OnPropertyChanged("Answer1");
      OnPropertyChanged("Answer2");
    }
  }

  public string Answer1
  {
    get
    {
      if(fullAnswer == null) return null;

      var tokens = fullAnswer.Split('.');
      if(tokens.Length < 1) return string.Empty;

      return tokens[0];
    }
  }

  public string Answer2
  {
    get
    {
      if(fullAnswer == null) return null;

      var tokens = fullAnswer.Split('.');
      if(tokens.Length < 2) return string.Empty;

      return tokens[1];
    }
  }

  protected void OnPropertyChanged(string propertyName)
  {
    var handler = this.PropertyChanged;

    if(handler != null)
      handler(this, new PropertyChangedEventArgs(propertyName));
  }
}