Number of lines in a Field of type Text with Javascript

Question

Hi,
I have a form where I need to dynamically retrieve the number of lines in a Field of type Text.
When I use getField(), I'm returned an object of type Field. I can see such properties as rect, but nothing concerning the number of lines of text in the field.
Any idea (other than getting the Field height and dividing that by the height of a line) ?
Regards,
Karl.

Answer 1

Hi,
You can use below function to calculate the no of lines in the Text field dynamically.
import mx.controls.textClasses.TextRange;
    import flash.text.TextField;
    private function calculateNoOfLines():int
      var tr2:TextRange = new TextRange(_text, true, 0,_text.text.length-1);
      tr2.text = _text.text;
      _text.invalidateSize();
      _text.invalidateDisplayList();
      _text.invalidateProperties();
      var contentTextField:TextField = _text.mx_internal::getTextField();                           
              var nLines:int = contentTextField.numLines;
              var lineMetrics:TextLineMetrics = _text.getLineMetrics(0);
              // This is to calculate the total text height
              var _textHeight:Number = lineMetrics.height * nLines;
     return nLines;    
Call the above function in the KeyUp event of the Text field.
Here in the above field _text is the Text field.
<mx:Text id="_text" />
If this post answers your question or helps, please kindly mark it as such.
Thanks,
Bhasker Chari