CODEWITHSUNDEEP
reactjs
SHAWAN
SHAWAN

Reputation: 1

Prooblem on select in react

I want to create a select component of Blood group option. I write code and it does render on dom but it is not showing up in the browser.

This is FindDonor Component 

import React, { Component } from "react";

class FindDonor extends Component {
  state = {
    value: "Find Donor By Blood Group"
  };

  handleChange = e => {
    this.setState({ value: e.target.value });
  };

  render() {
    return (
      <div className="findDonor">
        <h1>Hello</h1>
        <div className="input-field">
          <select value={this.state.value} onChange={this.handleChange}>
            <option value="a+">A+</option>
            <option value="o+">O+</option>
            <option value="b+">B+</option>
            <option value="ab+">AB+</option>
            <option value="a-">A-</option>
            <option value="o-">O-</option>
            <option value="b-">B-</option>
            <option value="ab-">AB-</option>
          </select>
        </div>
      </div>
    );
  }
}

export default FindDonor;

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>

Home Component code Home.js

App Component code App.js

Upvotes: 0

Views: 42

Answers (2)

fahad tufail
fahad tufail

Reputation: 615

I think you need to pass event on your onChange onChange={(e) => {this.handleChange(e)}. Also, in case of arrow functions, there is no need to bind functions.

class FlavorForm extends React.Component {
  constructor(props) {
    super(props);
    this.state = {value: 'coconut'};
  }

  handleChange = (event) => {
    this.setState({value: event.target.value});
  }

  handleSubmit = (event) => {
    alert('Your favorite flavor is: ' + this.state.value);
    event.preventDefault();
  }

  render() {
    return (
      <form onSubmit={this.handleSubmit}>
        <label>
          Pick your favorite flavor:
          <select value={this.state.value} onChange={(e) => {this.handleChange(e)}}>
            <option value="grapefruit">Grapefruit</option>
            <option value="lime">Lime</option>
            <option value="coconut">Coconut</option>
            <option value="mango">Mango</option>
          </select>
        </label>
        <input type="submit" value="Submit" />
      </form>
    );
  }
}

Upvotes: 0

ummahusla
ummahusla

Reputation: 2063

You are probably missing a this.handleChange = this.handleChange.bind(this); in your constructor.

Check this example from the React docs (https://reactjs.org/docs/forms.html#the-select-tag):

class FlavorForm extends React.Component {
  constructor(props) {
    super(props);
    this.state = {value: 'coconut'};

    this.handleChange = this.handleChange.bind(this);
    this.handleSubmit = this.handleSubmit.bind(this);
  }

  handleChange(event) {
    this.setState({value: event.target.value});
  }

  handleSubmit(event) {
    alert('Your favorite flavor is: ' + this.state.value);
    event.preventDefault();
  }

  render() {
    return (
      <form onSubmit={this.handleSubmit}>
        <label>
          Pick your favorite flavor:
          <select value={this.state.value} onChange={this.handleChange}>
            <option value="grapefruit">Grapefruit</option>
            <option value="lime">Lime</option>
            <option value="coconut">Coconut</option>
            <option value="mango">Mango</option>
          </select>
        </label>
        <input type="submit" value="Submit" />
      </form>
    );
  }
}

Upvotes: 1

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