index.js

import React from "react";


export default class Select extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      projects: [],
      value: 1
    };
  }


  componentDidMount() {
    console.log(this.props.list);


    this.setState({
        projects: this.props.list,
        value: 1
      });

  }
  handleClick() {
    this.setState({
      projects: [
        { id: 4, name: "水果" },
        { id: 5, name: "西瓜" },
        { id: 6, name: "哈哈哈" }
      ],
      value: 4
    });
  }
  handleChange = e => {
    this.setState({
      value: e.target.value
    });

    this.props.changeValue(e.target.value)
    console.log(e.target.value);
  };
  render() {
    let projects = this.state.projects;
    return (
      <div>
        <select
           value={this.state.value}
           onChange={this.handleChange}
        >
          {projects.length > 0 &&
          projects.map((item, i) => {
            return (
              <option key={i} value={item.name}>
                {item.name}
              </option>
            );
          })}
        </select>
      </div>
    );
  }
}