javascript 等待带有ajax调用的函数在jquery中完成执行
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wait till functions with ajax calls finish execution in jquery
提问by Nikki
i have 3 functions and in each function i have a AJAX call which is synchronous in nature.
我有 3 个函数，在每个函数中我都有一个 AJAX 调用，它本质上是同步的。
function()
{
a();
b();
c();
}
a()
{
ajaxGet(globals.servicePath + '/Demo.svc/GetDemoList/' + sessionStorage.SessionId,function(data, success) {}, '', {async: false}, false);
}
similarly for b() and c().
b() 和 c() 类似。
now i want to wait for the execution of these calls and then proceed with the other operations since those operations are based on the result i get here. how can i get this done?
现在我想等待这些调用的执行，然后继续其他操作，因为这些操作是基于我在这里得到的结果。我怎样才能做到这一点？
回答by Gone Coding
- A: never use
async: false. That way leads to the dark side! - B: see A :)
- 答：从不使用
async: false。那样会导致黑暗面！ - B: 见 A :)
One solution is the use the jQuery promises returned from Ajax calls.
一种解决方案是使用从 Ajax 调用返回的 jQuery 承诺。
If you want to know when all 3 are done (asynchronously in any order) use $.when():
如果您想知道所有 3 项何时完成（以任何顺序异步），请使用$.when()：
function()
{
$.when(a(), b(), c()).done(function(){
// Now do something else
});
}
and get each method to the return the jQuery promise of the Ajax call:
并获取每个方法以返回 Ajax 调用的 jQuery 承诺：
function a()
{
return $.ajax(globals.servicePath + '/Demo.svc/GetDemoList/' + sessionStorage.SessionId,function(data, success) {}, ''...);
}
I mocked up some fake "ajax calls" using timers to show this:
我用计时器模拟了一些假的“ajax 调用”来显示这一点：
JSFiddle:http://jsfiddle.net/TrueBlueAussie/rqq41Lg3/
JSFiddle：http : //jsfiddle.net/TrueBlueAussie/rqq41Lg3/
If, for some reason, you want them to run sequentially, then fire your extra code, you can chain them with then
如果出于某种原因，您希望它们按顺序运行，然后触发您的额外代码，您可以将它们链接起来 then
a().then(b).then(c).done(function(){
console.log("All done");
});
JSFiddle:http://jsfiddle.net/TrueBlueAussie/rqq41Lg3/1/
JSFiddle：http : //jsfiddle.net/TrueBlueAussie/rqq41Lg3/1/
