Question

我有几个ajax方法，我想在成功完成所有这些ajax调用后执行一些代码。我无法改变或重新定义ajax方法。请让我知道，如何实现这一目标。

我尝试使用WHEN，但它会立即调用，而不是等待所有调用完成。（正如所建议的，一旦我在loadData1（）中添加了返回，它就可以正常工作。）

现在我的问题是，如果任何请求（loadData1（）或loadData2（））有错误，那么“then（）”没有被执行。请告诉我，如何实现这一目标。

var load1 = loadData1();
var load2 = loadData2();
var load3 = loadData3();
var load4 = loadData4();

$.when(load1, load2, load3,load4).then(function () {
        console.log("All done");
});

function loadData1() {
    return $.getJSON("http://10.1.2.3/cgi-bin/GetData1.cgi", function (data) {
        console.log(data);
    });
}

由于

Answer 1

您可以使用

之类的功能

 function first() {
   return $.ajax(...);
}

function second(data, textStatus, jqXHR) {
   return $.ajax(...);
}

function third(data, textStatus, jqXHR) {
   return $.ajax(...);
}

function main() {
    first().then(second).then(third);
}

查看此详细信息jquery-promises

Answer 2

试试这个

var promise = loadData1();


var load2 = loadData2();
var load3 = loadData3();
var load4 = loadData4();

 promise.then(loadData2).then(loadData3).then(loadData4).then(function (E) {
                       //
                    });

function loadData1() {
    $.getJSON("http://10.1.2.3/cgi-bin/GetData1.cgi", function (data) {
        console.log(data);
    });

var deferred = new $.Deferred();
    deferred.resolve();
    return deferred.promise();
}

Answer 3

您应该在功能中返回一些内容。这是第一件事。第二个等待时，您必须等待功能结果，而不是-(BOOL)application:(UIApplication *)application continueUserActivity:(NSUserActivity *)userActivity restorationHandler:(void (^)(NSArray * _Nullable))restorationHandler使用load1, load2, load3, load4。

下面是一个模拟4个延迟函数（你的ajax请求）的例子。

＆＃13;

load1(), load2(), load3(), load4()

＆＃13;

// load1, load2, load3, load4 are defined to simulate promises and some work behind it

// here is var load1 = loadData1();
var load1 = function () {
    return $.Deferred(function(defer) {
        setTimeout(function() {
            $('#log').append('<div>loadData1()</div>');
            defer.resolve();
        }, 150);
    });
}

// here is var load2 = loadData2();
var load2 = function () {
    return $.Deferred(function(defer) {
        setTimeout(function() {
            $('#log').append('<div>loadData2()</div>');
            defer.resolve();
        }, 600);
    });
}

// here is var load3 = loadData3();
var load3 = function () {
    return $.Deferred(function(defer) {
        setTimeout(function() {
            $('#log').append('<div>loadData3()</div>');
            defer.resolve();
        }, 300);
    });
}

// here is var load4 = loadData4();
var load4 = function () {
    return $.Deferred(function(defer) {
        setTimeout(function() {
            $('#log').append('<div>loadData4()</div>');
            defer.resolve();
        }, 200);
    });
}


$(document).ready(function() {
    $.when(load1(), load2(), load3(), load4())
        .then(function () {
            $('#log').append('<div>All done.</div>');
        });
});

＆＃13;

Answer 4

您可以尝试使用像

这样的实用程序功能

Dim conServer As ADODB.Connection
Dim rstResult As ADODB.Recordset
Dim strSQL As String
Set conServer = New ADODB.Connection
conServer.ConnectionString = "PROVIDER=SQLOLEDB; " _
& "DATA SOURCE=192.168.0.204; " _
& "INITIAL CATALOG=REPORTDB2; " _
& "User ID=sa;" _
& "Password="

conServer.Open

Set rstResult = New ADODB.Recordset
strSQL = "set nocount on; "
strSQL = strSQL & "select *  from Table1;"
rstResult.ActiveConnection = conServer

rstResult.Open strSQL

MsgBox rstResult.RecordCount, , rstResult.Fields(1).Value

With rstResult
    .MoveFirst
    Do Until rstResult.EOF
       Debug.Print abc & "," & .Fields(0) & "," & .Fields(1).Value
      .MoveNext
    Loop
End With

然后

function allCompleted(array) {
  var deferred = jQuery.Deferred(),
    counter = array.length,
    results = [];
  $.each(array, function(i, item) {
    item.always(function() {
      results[i] = [].slice.call(arguments, 0)
      if (--counter == 0) {
        deferred.resolveWith(undefined, results);
      }
    });
  });
  return deferred.promise();
}

演示：Fiddle

jquery - 使用WHEN和DONE序列化ajax调用

4 个答案: