Question

Trying to bind a String to a RichTextBox.Text property so that when the String value changes, that change is reflected in the RichTextBox. So far I’m unsuccessful.

string test = "Test";
rtxt_chatLog.DataBindings.Add("Text",test,null);
test = "a";

This shows “Test” in the rtxt_chatLog, but not the “a”.

Even tried adding rtxt_chatLog.Refresh(); but that does not make any difference.

Update 1:
This does not work either:

public class Test
{
    public string Property { get; set; }
}

Test t = new Test();
t.Property = "test";
rtxt_chatLog.DataBindings.Add("Text", t, "Property");
t.Property = "a";

Am I not understanding data binding correctly?

Answer 1

The String class doesn’t implement INotifyPropertyChanged, so there are no events for the binding source to tell the RichTextBox that something changed.

Try updating your class with the INotifyPropertyChanged implemented:

public class Test : INotifyPropertyChanged {
  public event PropertyChangedEventHandler PropertyChanged;

  private string _PropertyText = string.Empty;

  public string PropertyText {
    get { return _PropertyText; }
    set {
      _PropertyText = value;
      OnPropertyChanged("PropertyText");
    }
  }

  private void OnPropertyChanged(string propertyName) {
    if (PropertyChanged != null)
      PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
  }

}

Also, it looks like DataBinding doesn’t like the name “Property” for a property name. Try changing it to something else other than “Property”.

rtxt_chatLog.DataBindings.Add("Text", t, "PropertyText");