React.js:如何在点击时附加组件？

Question

我是React的新手,我对某些基本的东西感到困惑.

我需要在呈现DOM之后,在click事件上将组件附加到DOM.

我最初的尝试如下,它不起作用.但这是我认为最好的尝试.(事先道歉,将jQuery与React混合使用.)

    ParentComponent = class ParentComponent extends React.Component {
      constructor () {
        this.addChild = this.addChild.bind(this);
      }

      addChild (event) {
        event.preventDefault();
        $("#children-pane").append(<ChildComponent/>);
      }

      render () {
        return (
          <div className="card calculator">
            <p><a href="#" onClick={this.addChild}>Add Another Child Component</a></p>
            <div id="children-pane">
              <ChildComponent/>
            </div>
          </div>
        );
      }
    };

希望很清楚我需要做什么,希望你能帮我找到合适的解决方案.

Answer 1

在使用React时,不要使用jQuery来操作DOM.React组件应该表示在给定某个状态时它们应该是什么样子; 翻译的DOM由React自己处理.

你想要做的是将"确定要渲染的内容的状态"存储在链的上方,并将其传递下去.如果要呈现n子项,则该状态应由包含组件的任何内容"拥有".例如:

class AppComponent extends React.Component {
  state = {
    numChildren: 0
  }

  render () {
    const children = [];

    for (var i = 0; i < this.state.numChildren; i += 1) {
      children.push(<ChildComponent key={i} number={i} />);
    };

    return (
      <ParentComponent addChild={this.onAddChild}>
        {children}
      </ParentComponent>
    );
  }

  onAddChild = () => {
    this.setState({
      numChildren: this.state.numChildren + 1
    });
  }
}

const ParentComponent = props => (
  <div className="card calculator">
    <p><a href="#" onClick={props.addChild}>Add Another Child Component</a></p>
    <div id="children-pane">
      {props.children}
    </div>
  </div>
);

const ChildComponent = props => <div>{"I am child " + props.number}</div>;

Answer 2

正如@Alex McMillan所提到的,使用state来决定dom中应该呈现的内容.

在下面的示例中,我有一个输入字段,我想在用户单击按钮时添加第二个字段,onClick事件处理程序调用handleAddSecondInput(),它将inputLinkClicked更改为true.我使用三元运算符来检查truthy状态,它呈现第二个输入字段

class HealthConditions extends React.Component {
  constructor(props) {
    super(props);


    this.state = {
      inputLinkClicked: false
    }
  }

  handleAddSecondInput() {
    this.setState({
      inputLinkClicked: true
    })
  }


  render() {
    return(
      <main id="wrapper" className="" data-reset-cookie-tab>
        <div id="content" role="main">
          <div className="inner-block">

            <H1Heading title="Tell us about any disabilities, illnesses or ongoing conditions"/>

            <InputField label="Name of condition"
              InputType="text"
              InputId="id-condition"
              InputName="condition"
            />

            {
              this.state.inputLinkClicked?

              <InputField label=""
                InputType="text"
                InputId="id-condition2"
                InputName="condition2"
              />

              :

              <div></div>
            }

            <button
              type="button"
              className="make-button-link"
              data-add-button=""
              href="#"
              onClick={this.handleAddSecondInput}
            >
              Add a condition
            </button>

            <FormButton buttonLabel="Next"
              handleSubmit={this.handleSubmit}
              linkto={
                this.state.illnessOrDisability === 'true' ?
                "/404"
                :
                "/add-your-details"
              }
            />

            <BackLink backLink="/add-your-details" />

          </div>
         </div>
      </main>
    );
  }
}