Question

我有一个名为items的变量。如果我在getjson函数中访问它的值，我得到正确的值。但如果我在getJSON函数之外访问它的值，我会得到字符串空值。我需要你的帮助来了解什么是问题。谢谢你的帮助！提前

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Answer 1

当你显示getJSON变量之外的项的值时，它是正常的，因为它在$ .getJSON方法的成功回调时获取其值，换句话说，你想在初始化时以同步模式显示它并取其值在异步模式下，你可以通过使用.done（）来解决这个问题，你的代码将变成如下：

$("#CityId").click(function () {
            var htmlText = "<ul class=ulList>";
            var mainDiv = $('.divCounties');
        var items = "";

            for (var i = 0; i < arrCity.length; i++) {

                htmlText += "<li class=ilceCaption>" + arrCity[i].text; // +"</li>";

                htmlText += "<ul>";

                $.getJSON("../Adds/GetCounties", { cityId: arrCity[i].value },
            function (data) {

                $.each(data, function (i, state) {
                    items += state.Text;
                //htmlText += "<li>" + state.Text + "</li>";

                }); 
    console.log(items); **// ==> is getting correct value in this line**                
            }).done(function() {
    console.log( "second success" );
    console.log(items);
  });

            htmlText += "</ul>";
            htmlText += "</li>";


            }

            htmlText += "</ul>";
            console.log(htmlText);

      mainDiv.html(htmlText);

Answer 2

您应该使用承诺和完成功能：

$("#CityId").on('click',function(e){
    e.preventDefault();
    var htmlText = "<ul class=ulList>";
    var mainDiv = $('.divCounties');
    var items = "";
    for (var i = 0; i < arrCity.length; i++) {
        htmlText += "<li class=ilceCaption>" + arrCity[i].text; // +"</li>";
        htmlText += "<ul>";
        $.getJSON("../Adds/GetCounties", {cityId: arrCity[i].value }, function(data){
            $.each(data, function(i, state) {
                items += state.Text;
                //htmlText += "<li>" + state.Text + "</li>";
            }).promise().done(function(){
                console.log(items);
            })
        });
        htmlText += "</ul>";
        htmlText += "</li>";
        console.log(items);
    }
    htmlText += "</ul>";
    console.log(htmlText);
    mainDiv.html(htmlText);
});

How to Jquery each complete

无法在getJSON函数之外获取正确的变量值

2 个答案: