javascript - react : Perform different operation depending on select option dropdown

Question

我在 React 中有以下形式。如果选择标签中的选项是参与，我想做的是发送一个 POST 请求。

<form action={this.props.action} method="POST" onSubmit={this.handleSubmit}>
    <div className="ui action input">
        <input type="text" placeholder="Enter code" name="code"/>
        <select className="ui compact selection dropdown">
            <option value="participate">Participate!</option>
            <option value="check_status">Check status</option>
         </select>
         <button>
             Submit
         </button>
     </div>
 </form>

这是我的 handleSubmit 函数:

handleSubmit = (event) => {
    event.preventDefault();

    // HERE I want to check if the option as Participate, and then to the following code:

    // Sudo code here
    // IF STATEMENT event.target.value.option === 'participate'

    const data = {id: this.state.code, is_winner: true};

    fetch('/api/add_user', {
        method: 'POST',
        headers: {
            'Content-type': 'application/json',
        },
        body: JSON.stringify(data),
    })
        .then(res => res.json());

    // ElSE
    // DO NOT SOMETHING ELSE (NOT POST)
};

Answer 1

要以“React”方式执行此操作，您需要捕获选择框的 onChange 事件:

<select onChange={e=>this.setState({selectedOption:e.target.value})} className="ui compact selection dropdown">

然后你的条件检查将是这样的:

if (this.state.selectedOption === 'participate') {...