How to solve the problem that ExtJs cannot transfer and assign values asynchronously?-JS Tutorial-php.cn

How to solve the problem that ExtJs cannot transfer and assign values asynchronously?

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Release： 2017-06-26 09:49:04

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1. The Ext.data.Store.load(); method is asynchronous. The reCount obtained in the following way is always 0, because the value is assigned before the background method is executed. At this time, the store The record has not yet obtained a value.

var testStore = new Ext .data.GroupingStore({

proxy : new Ext.data.HttpProxy({

## # reader :

new

Ext.data.JsonReader({

root: 'hstamcx',

## totalProperty:

"results" ,

fields: ["id","value"

]

## })##});Ext.onReady(

function

(){

Ext.QuickTips.init();

## Ext.form.Field.prototype.msgTarget = 'side';

testStore.load ();

var reCount = testStore.getCount();

var

port = new

Ext.Viewport({

## Layout ## });});#2. If you want to process the loaded value, you must write the subsequent processing in the callback function.

Ext.onReady(

function(){

Ext.QuickTips.init();
testStore.load({                                                                                                             ##var reCount = test
Store.getCount();
#

##var port =
new

Ext.Viewport({

                                                                                                                              Layout:

'auto'
,                 frame: true,##                       items: [winKey]

});});

The value of reCount can be obtained at this time, and callback: The r of function(r, options, success) is the data found by the store loading. But there is still a problem: r’s data value can only be used in the callback function. In the callback function, there is no way to assign values to other external elements, and there is no way to use r Transfer the data to the outside

3. If you want to send a request to the background on the js page and use the data value returned by the background outside, you can use
Ext.Ajax.request, and
set the request mode to synchronous, and the variables to receive data must be defined outside
Ext.Ajax.request


cancelMode;

##                                                       url: '

, ## Method: ' Post '
#,
                  sync:
true
,

//Synchronous request#                 Success: function

(response) {
                   var response = Ext.util.JSON.decode(response.responseText);

                                                                                                                                  cancelMode = response.hstamcx[0].param_value; At this time, you can use the data obtained by
Ext.Ajax.request request outside, such as alert(
cancelMode
);

Backend code example: This example is a rough example, not a complete code

public void

getData(

HttpServletResponse response){# TestData td = TestDataDao.getTestdata() ; String message = "{name:" + td
.getName()
+
",id:"
+ td.getId()+
"}"; PrintWriter out=response.getWriter();
## out.write(message);

out.flush();
}

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