How to use the WeChat mini program drop-down box component

This article mainly introduces the use of the drop-down box component of the WeChat applet in detail. It is written in a very comprehensive and detailed manner and has a certain reference value. Friends in need can refer to it for learning. Down. If there are any deficiencies, criticisms and corrections are welcome. [Recommended tutorial: 小program development tutorial]

Applicable scenarios

1. Three-level linkage between provinces and cities
2. Date of birth selection
3.Gender Selection
4, general drop-down selection, etc.

1. Provincial and municipal three-level linkage use

Note mode = region, and value = "One-dimensional array ”

//.wxml
<picker mode="region" bindchange="bindViewEvent" data-model="component"
data-method="bindSelect" data-name="region" value="{{region}}" custom-item="{{customItem}}">
<view class="picker">
   当前选择：{{region[0]}}，{{region[1]}}，{{region[2]}}
</view>
</picker>

2. Birth date selection

Note mode = date, and value = “date string”

<picker mode="date" value="{{date}}" start="2015-09-01" end="2017-09-01" bindchange="bindViewEvent" data-model="component" data-method="bindSelect" date-mode="date" data-name="date">
  <view class="picker">
  {{date}}
  </view>

3. Gender selection

<picker bindchange="bindViewEvent" data-model="component" data-method="bindSelect" data-name="index" value=&#39;{{index}}&#39; range="{{gender}}">
  <view class="label-right">
    {{gender[index]}}
  </view>
</picker>

All of the above need to set relevant initial variables in .js!

var app = getApp();
 data: {
  region:['湖南','长沙','岳麓'],
  date:'2010-10-10',
  gender:['男','女'],
  index:0
 }
 bindViewEvent:function(e){
  app.process(this,e);  
 }

Related js classes

//component.js
const select = require('../component/select.js');
const upload = require('../component/upload.js');
class component{
 constructor(com, that) {
  this.com = com;
  this.that = that;
 }
 //绑定下拉框选择事件
 bindSelect(data){
  let self = this;
  let mode = data.currentTarget.dataset.mode;
  let name = data.currentTarget.dataset.name;
  let picker = new select({
   that: self.that,
   mode: mode,
   name: name
  });
  picker.change(data.detail.value);
 }
 //点击事件，传递参数为e.currentTarget.dataset
 bindImageChoose(data){
  //图片上传
  this.uploader = new upload({
   that: that,
   name: data.name,
   mode: data.mode,
   count: data.count || 9
  });
  this.uploader.choose();
 }
 bindImageDel(data){
  //图片上传
  this.uploader = new upload({
   that: that,
   name: data.name,
   mode: data.mode,
   count: data.count || 9
  });
  this.uploader.del(data.index);
 }
}
module.exports = component;
//select.js
/*
* 下拉框对象
*/
class picker{
 constructor(data){
  this.that = data.that;
  this.name = data.name || 'date';
  this.mode = data.mode || 'selector';
 }
 show(name,data){
  let view = {};
  view[name] = data;
  this.that.setData(view);
 }
 change(data){
  let self = this;
  self.show(self.name, data);
 }
}
module.exports = picker;
//upload.js
class picUploader {
 constructor(data) {
  this.that = data.that;
  this.name = data.name;
  this.mode = data.mode || 1;
  this.count = this.model == 1 ? 1 : data.count || 9;
 }
 /*
 * 选择图片
 */
 choose() {
  const self = this;
  wx.chooseImage({
   count: (self.count - self.that.data[self.name].length),
   sizeType: ['original', 'compressed'],
   sourceType: ['album', 'camera'],
   success: function (res) {
    var tempFilePaths = res.tempFilePaths;
    self.append(tempFilePaths);
   }
  })
 }
 /*
 * 显示图片
 */
 show() {
  let self = this;
  let view = {};
  view[self.name] = self.that.data[self.name];
  self.that.setData(view);
 }
 /*
 * 追加图片
 */
 append(data) {
  const self = this;
  for (let i = 0; i < data.length; i++) {
   self.that.data[self.name].push(data[i]);
  }
  self.show();
 }
 /*
 * 删除图片
 */
 del(index) {
  let self = this;
  self.that.data[self.name].splice(index, 1);
  self.show();
 }
}
module.exports = picUploader;

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