setTexFormat is not wroking?

Hi, Why this format is not working ?? can anyone tell me. I want my textfield set to be dynamic and dont want to fix its W x H

otherdataFormat=new TextFormat();
otherdataFormat.font=“verdana”;
otherdataFormat.align=“left”;
otherdataFormat.size=10;
otherdataFormat.multiline=true;
otherdataFormat.autoSize=true;
otherdataFormat.wordWrap=true;
this.createTextField(“a”, 1, 100, 100, 20, 20);

this[“a”].text = “ashish CJAHJDH SNDFJKA JKDNKAS BNFAFNSF BKASNFasdasdsd”
this[“a”].setTextFormat(otherdataFormat)

Thanx
Ash