Custom Widget: Question regarding model selection


I would like to use the model selection. For this I have two questions:

  1. In the name attribute, I would like to display an item as a string. In this case, a temperature. I can’t get that to work. Is that possible?
  2. Unfortunately, the value of the item does not change if I choose another value via the widget. Do I have to pay attention to something?
<div class="set-val" ng-init="model = {
                name: config.temp_set,
                item: config.temp_set,
                square: true,
                choices_rows: 3,
                choices_columns: 3,
                choices_source: 'csv',
                no_highlight: true,
                hidestate: true,
                choices: '18=18 °C,19=19 °C,19.5=19.5 °C,20=20 °C,20.5=20.5 °C,21=21 °C,21.5=21.5 °C,22=22 °C,23=23 °C'
	<widget-selection ng-model="model"></widget-selection>