<table id="testTable">
 <tr v-for="(el, lineIndex) in lines" v-line-inserted="lineIndex" >
  <td>
   <input name="bindSelect2" />
  <td>
 </tr>
</table>
function renderLines(el, lineIndex){
 //渲染select2
 $("testTable tr").eq(lineIndex).select2({...});
}

Vue.directive('line-inserted', {
 inserted: function (el, binding) {
  var lineIndex = binding.value;
  renderLines(el, lineIndex);
 }
});