Question

我有一个问题，当我调用这个返回bool的函数时，我得到bool undefined。它应该返回我bool值我试过var bool = funcationName（）但它返回undeffiend

IsaAtionResultExist

createAction

  $("#createAction").click(function() {


    var bools = IsaAtionResultExist(Clinetfirstname, Clinetlastname, datasource, status, cliendid);
                    if (bools === true) {
                    return false;
  }      
});
  }
});

IsaAtionResultExist 在警报中显示为

   function IsaAtionResultExist(Clinetfirstname, Clinetlastname, datasource, status, cliendid) {
        alert("Second");
        debugger;
        $.ajax({
            type: "GET",
            url: '@Url.Action("IsaAtionResultExist", "P4C")',

            data: { Clinetfirstname: Clinetfirstname, Clinetlastname: Clinetlastname, datasource: datasource, status: status, cliendid: cliendid },

            success: function (data) {
                if (data === true) {
                    alert(data);
                    return data;
                } else {
                    return false;
                }
            }
        });

    }

Answer 1

您正在尝试从ajax回调中返回数据，这是不可能的。 Javascript是异步的，因此包装函数不会返回ajax回调返回。

Answer 2

$.ajax(...)是一个返回promise的异步调用，只能在promise解析后检查boolean。我已经更改了您的AJAX函数以返回该承诺，如下所示：

function IsaAtionResultExist(Clinetfirstname, Clinetlastname, datasource, status, cliendid) {
    return $.ajax({
        type: "GET",
        url: '@Url.Action("IsaAtionResultExist", "P4C")',
        data: {
            Clinetfirstname: Clinetfirstname,
            Clinetlastname: Clinetlastname,
            datasource: datasource,
            status: status,
            cliendid: cliendid
        },
        success: function (data) {
            if (data === true) {
                alert(data);
                return data;
            } else {
                return false;
            }
        }
    });
}

然后在您的点击事件中，您需要执行以下操作：

$("#createAction").click(function() {                     
    IsaAtionResultExist(Clinetfirstname, Clinetlastname, datasource, status, cliendid)
    .done((bools) => {
         // do something with your bools
         // but not a return statement unless you need it for a successive
         // callback chain
    };
});

jQuery函数返回undefined，期待bool

2 个答案: