Javascript 传递包含参数的回调函数？
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Passing a callback function with included parameters?
提问by Brett
I have this below code..
我有这个下面的代码..
function getGrades(grading_company) {
if (grading_company == 'Not Specified') {
// Remove grades box & show condition box
showConditionBox();
} else {
// Set file to get results from..
var loadUrl = "ajax_files/get_grades.php";
// Set data string
var dataString = 'gc_id=' + grading_company;
// Set the callback function to run on success
var callback = showGradesBox;
// Run the AJAX request
runAjax(loadUrl, dataString, callback);
}
}
function runAjax(loadUrl, dataString, callback) {
jQuery.ajax({
type: 'GET',
url: loadUrl,
data: dataString,
dataType: 'html',
error: ajaxError,
success: function(response) {
callback(response);
}
});
}
Edit:Here is the function that gets called as the callback function:
编辑：这是作为回调函数调用的函数：
function showGradesBox(response) {
// Load data into grade field
jQuery('#grade').html(response);
// Hide condition fields
jQuery('#condition').hide();
jQuery('#condition_text').hide();
// Show grade fields
jQuery('#grade_wrapper').show();
jQuery('#grade_text_wrapper').show();
}
Now if I wanted to pass the grading_companyvariable to the callback function as a parameter is there a way to do that without having to add it as another parameter in the runAjaxcall? I'm trying to keep the runAjaxfunction open to other usage so I don't want to pass in any extra parameters; but if it can somehow be included within the callback then great.
现在，如果我想将grading_company变量作为参数传递给回调函数，有没有办法做到这一点，而不必在runAjax调用中将其添加为另一个参数？我试图保持该runAjax函数对其他用途开放，所以我不想传递任何额外的参数；但如果它可以以某种方式包含在回调中，那就太好了。
回答by jbabey
change your callback to an anonymous function:
将您的回调更改为匿名函数：
// Set the callback function to run on success
var callback = function () {
showGradesBox(grading_company);
};
This allows you to pass parameters to the inner function.
这允许您将参数传递给内部函数。
Edit: to allow for the ajax response:
编辑：允许 ajax 响应：
// Set the callback function to run on success
var callback = function (response) {
showGradesBox(grading_company, response);
};
回答by jwatts1980
Another possibility is instead of doing dataStringdo dataObjectthen pass that object to the callback. Like so:
另一种可能性是不做dataStringdodataObject然后将该对象传递给回调。像这样：
function getGrades(grading_company) {
if (grading_company == 'Not Specified') {
// Remove grades box & show condition box
showConditionBox();
} else {
// Set file to get results from..
var loadUrl = "ajax_files/get_grades.php";
// Set data object
var dataObject = {
'gc_id' : grading_company
/*to do multiples..
'item1' : value1,
'item2' : value2,
'etc' : etc */
}
// Set the callback function to run on success
var callback = showGradesBox;
// Run the AJAX request
runAjax(loadUrl, dataObject, callback);
}
}
function runAjax(loadUrl, dataObject, callback) {
jQuery.ajax({
type: 'GET',
url: loadUrl,
data: $.param(dataObject),
dataType: 'html',
error: ajaxError,
success: function(response) {
callback(response, dataObject);
}
});
}
Note the addition of $.param().
注意添加$.param().
Then in the callback function, you should know what data you're after. If function setGrades(resp, data) { ... }was the callback, then you can access the values in setGrades
然后在回调函数中，你应该知道你要的是什么数据。如果function setGrades(resp, data) { ... }是回调，那么您可以访问中的值setGrades
function setGrades(resp, data) {
alert( data.gc_id);
}
EDIT
编辑
After testing, I realize that $(dataObject).serialize()will not work. So I've updated to use $.param(). Please see this SO postfor more info.
经过测试，我意识到这$(dataObject).serialize()行不通。所以我已经更新为使用$.param(). 请参阅此 SO 帖子以获取更多信息。
