Vue advanced (univariate): the solution that the view does not update after the Vue array or object is updated

No Silver Bullet 2020-11-13 07:28:49
vue advanced univariate solution view


In the process of project development , If you bind all page elements to a form , Some elements in the page are not directly obtained , The unexpected effect will appear when getting the page operation value , For example, page elements cannot be reset .

Scene: the repetition

In the use of el-select When designing a form drop-down box , If the length of the drop-down box array returned by the background is 1, The first element is selected by default . The idea is to return the value of the first element directly after the background value Assign a value to el-select Of v-model.

created() {
....
this.MissionTemplateForm.state = this.StatusOptions[0].display_name
},

But after the background method returns the value , by el-select Before assignment ,MissionTemplateForm It has been assigned a value response.returnobj, Lead to MissionTemplateForm The structure of is destroyed , So we need to be right MissionTemplateForm Reset the properties in the . Need to use

Vue.set( target, propertyName/index, value )

Everybody knows vue It is a bi-directional binding responsive update view , This auto update view is mainly aimed at data The key of an attribute or object that exists in it , Such as a data:{ test : 'test'}; Modify here test You can automatically update the relevant view with the value of , But if you add a new attribute later and change it It can't be updated automatically , This involves vue Two way binding principle of .

vue The default is to give data attribute Add to scout ( Publisher —— Subscriber pattern ) Upper observation , Respond to view updates if there are changes , The newly added attributes and objects do not perform this step of adding to the observer , Need to be manually added , It needs to be used VUE Of set The method is to .

Parameters :

The first parameter is the array or object you want to modify
{Object | Array} target

The second parameter is the name of the object to be modified or the corresponding subscript
{string | number} propertyName/index

The third parameter wants to modify the value after success

{any} value

Vue.set(app.arr,1,'qq')

The value returned is the third parameter value

Use it directly in your page method

 let obj = this.dryingList[ind];
this.$set(obj, "nodianzanflag", true);

Reference documents

https://cn.vuejs.org/v2/api/#Vue-set

Vue Advanced ( ninety-seven ):vue Add properties and values to an object dynamically

Vue Advanced ( Ninety-eight ):Vue.set() and this.$set() Introduce

版权声明
本文为[No Silver Bullet]所创,转载请带上原文链接,感谢

  1. [front end -- JavaScript] knowledge point (IV) -- memory leakage in the project (I)
  2. This mechanism in JS
  3. Vue 3.0 source code learning 1 --- rendering process of components
  4. Learning the realization of canvas and simple drawing
  5. gin里获取http请求过来的参数
  6. vue3的新特性
  7. Get the parameters from HTTP request in gin
  8. New features of vue3
  9. vue-cli 引入腾讯地图(最新 api,rocketmq原理面试
  10. Vue 学习笔记(3,免费Java高级工程师学习资源
  11. Vue 学习笔记(2,Java编程视频教程
  12. Vue cli introduces Tencent maps (the latest API, rocketmq)
  13. Vue learning notes (3, free Java senior engineer learning resources)
  14. Vue learning notes (2, Java programming video tutorial)
  15. 【Vue】—props属性
  16. 【Vue】—创建组件
  17. [Vue] - props attribute
  18. [Vue] - create component
  19. 浅谈vue响应式原理及发布订阅模式和观察者模式
  20. On Vue responsive principle, publish subscribe mode and observer mode
  21. 浅谈vue响应式原理及发布订阅模式和观察者模式
  22. On Vue responsive principle, publish subscribe mode and observer mode
  23. Xiaobai can understand it. It only takes 4 steps to solve the problem of Vue keep alive cache component
  24. Publish, subscribe and observer of design patterns
  25. Summary of common content added in ES6 + (II)
  26. No.8 Vue element admin learning (III) vuex learning and login method analysis
  27. Write a mini webpack project construction tool
  28. Shopping cart (front-end static page preparation)
  29. Introduction to the fluent platform
  30. Webpack5 cache
  31. The difference between drop-down box select option and datalist
  32. CSS review (III)
  33. Node.js学习笔记【七】
  34. Node.js learning notes [VII]
  35. Vue Router根据后台数据加载不同的组件(思考->实现->不止于实现)
  36. Vue router loads different components according to background data (thinking - & gt; Implementation - & gt; (more than implementation)
  37. 【JQuery框架,Java编程教程视频下载
  38. [jQuery framework, Java programming tutorial video download
  39. Vue Router根据后台数据加载不同的组件(思考->实现->不止于实现)
  40. Vue router loads different components according to background data (thinking - & gt; Implementation - & gt; (more than implementation)
  41. 【Vue,阿里P8大佬亲自教你
  42. 【Vue基础知识总结 5,字节跳动算法工程师面试经验
  43. [Vue, Ali P8 teaches you personally
  44. [Vue basic knowledge summary 5. Interview experience of byte beating Algorithm Engineer
  45. 【问题记录】- 谷歌浏览器 Html生成PDF
  46. [problem record] - PDF generated by Google browser HTML
  47. 【问题记录】- 谷歌浏览器 Html生成PDF
  48. [problem record] - PDF generated by Google browser HTML
  49. 【JavaScript】查漏补缺 —数组中reduce()方法
  50. [JavaScript] leak checking and defect filling - reduce() method in array
  51. 【重识 HTML (3),350道Java面试真题分享
  52. 【重识 HTML (2),Java并发编程必会的多线程你竟然还不会
  53. 【重识 HTML (1),二本Java小菜鸟4面字节跳动被秒成渣渣
  54. [re recognize HTML (3) and share 350 real Java interview questions
  55. [re recognize HTML (2). Multithreading is a must for Java Concurrent Programming. How dare you not
  56. [re recognize HTML (1), two Java rookies' 4-sided bytes beat and become slag in seconds
  57. 【重识 HTML ,nginx面试题阿里
  58. 【重识 HTML (4),ELK原来这么简单
  59. [re recognize HTML, nginx interview questions]
  60. [re recognize HTML (4). Elk is so simple