如何使用react触发变更事件

Question

Currently I have this function in backbone.

It update the model when onChange event is triggered.

bindElementToAttribute: function(el, name, eventType) {
    var that = this;
    eventType = typeof(eventType) != 'undefined' ? eventType : "change";
    $(el).on(eventType, function() {
      var obj = {};
      obj[name] = $(el).val();
      that.model.set(obj, {silent: true});
      return true;
    });

I'm using a datepicker component of react to add a date field in this model, but this function of backbone does not trigger the onChange event when I select the date. This is the component : https://github.com/Hacker0x01/react-datepicker

In my component, I manually triggered the 'change' event

handleChange(date) {
    this.setState({
      startDate: date
    });
    $('input[name=release_date]').trigger('change')
  }

This is working fine, but when I select a new date in the datepicker, it pass the old value to the model. When onchange is triggered the value has not yet updated.

How can I fix this?

Thanks everyone

Answer 1

This is probably because you trigger the event before your component re rendered as a result of setState , therefore you get the Dom's old value.

Two options to solve this:

1.You can pass setState a callback function as second parameter, like this:

this.setState({
  startDate: date
}, function(){$('input[name=release_date]').trigger('change')});

the callback function will be executed once setState is completed and the component is re-rendered.(read more here: http://reactjs.cn/react/docs/component-api.html#setstate ).

2.And more React-ish- pass a callback function as prop to your component and execute it handleChange instead of triggering an input change. like this:

handleChange(date) {
  this.setState({
    startDate: date
  });

  this.prop.onChangeCallback(date);
}

* You can execute the onChangeCallback , at specific points in your component's lifecycle. read about Lifecycle Methods to decide on which point.