[Vue] Vue gets data from the server and assigns it to data. How to render the updated view

Li gulare 2020-11-12 23:49:47
vue vue gets data server


The data from the server needs real-time feedback , Otherwise it will be meaningless !

Catalog

 

Introduce to you Vue.set() Method

One :data Define an object in :

Two : Send a request from the server to return the new data object :

3、 ... and : use Vue.set() Method update data

Let's introduce the second situation :

One : We are data A large temporary object is defined in

Two : We also define large objects in computational properties

3、 ... and : Initiate asynchronous request , Return data from the server

Four : How to use in the page template component


Let me introduce you first Vue.set() Method

notes : If the amount of data returned from the server is small , Or just a few fields , It can be used vue Of set Method , If the amount of data is large , Take a look at the second situation .

Official website API This is how it was introduced :

Vue.set(target,key,value)

Parameters :

{Object | Array} target

{string | number} key

{any} value

Return value : New value after setting

usage :

Add a property... To the responsive object , And make sure that the new property is also responsive , And trigger view update . It must be used to add new properties to the responsive object , because Vue Can't detect normal new properties ( such as this.myObject.newProperty = 'hi')

Attention object cannot be Vue example , perhaps Vue The root data object of the instance .

Let me give you a simple example , Introduce this usage :

One :data Define an object in :

data() {
return {
person:{
age:10,
name:' Liguulare ',
sex:1
}
}
}

Two : Send a request from the server to return the new data object :

person:{
age:20,
name:' Round and round ',
sex:0
}

In this case, you need to render the object to the page in real time

3、 ... and : use Vue.set() Method update data

As shown below :

methods: {
getPerson(){
this.$http({
method: "post",
url:this.$$baseURL + "sys/getPerson",
}).then(res => {
Vue.set(this.person,0,{age:res.data.age,name:res.data.name,sex:res.data.sex})
/**
* 0 What's updated is the location 0 The data on the
*
*/
});
}
}

In this way, the new data returned from the server is updated to the component in real time .

****************************** above (Vue.set() Usage method )*****************************************

Let me talk about the second situation :

In this case, there is a large amount of data , More fields , Use Vue.set() The method is a little too much , What should we do then ?

The core idea is to define a temporary variable , because computed It's computational properties , This value update can render the component in real time and update the page .

One : We are data A large temporary object is defined in

data() {
return {
myTempObj:{} // This is a big temporary object , There are so many fields
}
}

Two : We also define a large object in the calculated properties

This object is what we actually use on the page

computed: {
myObj: {
get: function(){
return this.myTempObj; // Here, the value of the temporary object is assigned to the object used in the page by calculating the properties
}
},
}

3、 ... and : Initiate asynchronous request , Return data from the server

methods: {
getBigObj(){
this.$http({
method: "post",
url:this.$$baseURL + "sys/getBigObj",
}).then(res => {
this.myTempObj=res.bigObj ; // Here we use the temporary variable to accept the server-side return value
});
}
}

Four : How to use in the page template component

<div class="brand-list bybrand_list" v-for="(item, index) in myObj" :key="index">
{
{item.name}}
</div>

The above two situations can solve the problem that the data obtained from the server cannot be updated in real time , According to the specific use of !

Four years java Development , Four years of front end products . Today's headlines, front-end architects . Welcome to follow me , Technological life is so interesting !

版权声明
本文为[Li gulare]所创,转载请带上原文链接,感谢

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