带有jQuery Ajax调用的MVC无法正确绑定空数组/可枚举 [英] MVC with jQuery Ajax call does not correctly bind empty array/enumerable
问题描述
我有一个jQuery ajax调用,我试图在其中发送可以从复选框表中选择的用户的int ID.
I have a jQuery ajax call in which I am trying to send the int IDs of users which can be selected from a table of checkboxes.
我没有选择任何用户的问题.我希望有一个空数组,但实际上我收到的是长度= 1的数组,其中包含userId 0(即,未分配的int值).
I am having a problem with the case that no users are selected. I would expect an empty array but in fact I receive an array of length = 1, containing userId 0 (i.e. an unassigned int value).
以下代码片段重现了问题
The following snippet reproduces the problem
$('#test').click(function () {
var numbers = $('.noElements').map(function () {
// (selector does not match any elements, to demonstrate)
return 1;
}).get();
$.ajax({
url: '/MyController/Test',
type: "GET",
data: { numbers: numbers, count: numbers.length }
});
});
public ActionResult Test(IEnumerable<int> numbers, int count)
{
Assert(numbers.Count() == count);
return null;
}
断言失败是因为 numbers
是 List< int>{0}
.为什么绑定是这样发生的?
The Assert fails because numbers
is List<int> { 0 }
. Why is the binding happening like this?
推荐答案
我相信默认模型联编程序会将jQuery AJAX调用传递给它的空字符串转换为包含单个元素的整数数组,该元素包含整数(0)的默认值.如果您执行以下操作,您的代码将起作用-
I believe that the default model binder will convert the empty string that is passed to it by the jQuery AJAX call into a integer array that contains a single element containing the default value of an integer (0). Your code would work if you did something like this-
$('#test').click(function () {
var numbers = $('.noElements').map(function () {
return 1;
});
if (numbers.length == 0) {
numbers = null;
count = 0;
}
else count = numbers.length;
$.ajax({
url: '/Home/Test',
type: "GET",
data: { numbers: numbers, count: count }
});
});
See this question for further info and alternate solutions - How to post an empty array (of ints) (jQuery -> MVC 3)
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