react-ref

• ref：react对真实dom的引用
• ref在reactElement上

 { this.div = ref; }}>
console.log(this.button)
> 真实的DOM

• ref在react组件上

 { this.button = ref; }}
    key={this.state.list}
    size='long'
    btnType='primary'
    isRadius={false}
    >{this.state.list}
console.log(this.button)
> Button {props: Object, context: Object, refs: Object, updater: Object, _reactInternalInstance: ReactCompositeComponentWrapper…}
//拿到的不是真实dom而是组件实例
//需要用ReactDom.findDOMNode来拿到真实DOM
ReactDom.findDOMNode(this.button)