Dart + Polymer，如何绑定到以编程方式生成的元素，textarea，select，optgroup

Question

I'm trying to create a form Polymer component where form elements are generated on the fly. I've looked, and so far the only way to bind the value attribute is by using .injectBoundHtml . This does not work with all component types, I'm trying to bind the value of a <textarea> , and this is what I get:

Removing disallowed attribute <TEXTAREA value="{{ results[ "comments" ] }}">

My work around was to add: textareaID.addEventListener('change', updateValueMap)

I'm hoping someone could tell me why value is disallowed, and/or if there is a better way to programmatically assign bound attributes in Polymer . Please :)!

Thanks to Gunter's suggestion, and passing a node validator:

var val = new NodeValidatorBuilder.common()
  ..allowElement('textarea', attributes:['value']);
this.injectBoundHtml(getElementStr(i), element:selP, validator:val);

Answer 1

Textarea doesn't have a value attribute. Try this instead

<textarea>{{results['comments']}}</textarea>

For more information about the message Removing disallowed attribute see How to create shadow DOM programmatically in Dart?