WPF binding to another property's binding in a style

Question

I\'m not sure the best way to ask this question (sorry for the ambiguous question title), but essentially I\'d like to set the MaxLength property on a TextBox using a value

Answer 1

Ok, after some more digging, I've figured this out to my satisfaction. I'm binding to RelativeSource Self and then parsing the binding expression on the Text property (since this is a TextFieldMaxLength converter, I am presuming I'm working against a TextBox.

The styling up in the resource dictionary:

The usage (basically showing nothing special needs to be done since it's all in the style):

The Convert Method for the textFieldMaxLengthConverter:

public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
  Control control = value as Control;
  BindingExpression be = control.GetBindingExpression(TextBox.TextProperty);
  if (be != null)
  {
    string boundPropertyName = be.ParentBinding.Path.Path;
    // .. boundPropertyName here is MyPropertyName.TheirPropertyname, do some parsing and return a value based on that
  }
}

(Obviously my actual implementation is a bit more complex/handles unexpected input/uses reflection as per my original question's statement).

Anyway, thought I would post this solution in case anyone else tries to do something similar, or if there might be a better way to do this than I am using.