Question

我的ajax电话看起来像这样

$.ajax({ //actually approve or reject the promotion
                url: url,
                type: "POST",
                data: '{'+data.PromotionId+','+data.UserId+','+data.ReasonText+'}',
                dataType: "json",
                //contentType: "application/json; charset=utf-8",
                success: function (data) {
                    if (indicator == 'A') {
                        alert('Promotion approved successfully!');
                    }
                    else {
                        alert('Promotion rejected successfully.');
                    }

                    var homelink = '<%: Url.Action("Index","Home") %>';
                    window.location.href = (homelink);


                    returndata = data;
                },
                error: function (xhRequest, ErrorText, thrownError) {
                    alert("Failed to process promotion correctly, please try again");
                    console.log('xhRequest: ' + xhRequest + "\n");
                    console.log('ErrorText: ' + ErrorText + "\n");
                    console.log('thrownError: ' + thrownError + "\n");
                }
            });

我的MVC控制器看起来像这样：

 [HttpPost]
    public HttpResponseMessage ApprovePromotion(PromotionDecision decision)
    {
        if (ModelState.IsValid && decision != null)
        {
            bool status = PromotionBo.ApprovePromotion(decision);
            if (status == true)
                return new HttpResponseMessage(HttpStatusCode.OK);
        }
        return new HttpResponseMessage(HttpStatusCode.BadRequest);
    }

我原本以为这两种语法都是正确的，但是每次我进行ajax调用时都得到400响应。我做错了什么？

Answer 1

您正在向服务器发送完全损坏且无效的JSON字符串。控制器动作拒绝它是正常的。除此之外，您已在contentType参数中添加了指定要发送JSON请求的参数。

所以这是执行请求的正确方法：

$.ajax({ //actually approve or reject the promotion
    url: url,
    type: "POST",
    data: JSON.stringify({ 
        // Those property names must match the property names of your PromotionDecision  view model
        promotionId: data.PromotionId, 
        userId: data.UserId, 
        reasonText: data.ReasonText
    }),
    contentType: "application/json; charset=utf-8",
    success: function (data) {
        if (indicator == 'A') {
            alert('Promotion approved successfully!');
        }
        else {
            alert('Promotion rejected successfully.');
        }

        var homelink = '<%: Url.Action("Index","Home") %>';
        window.location.href = (homelink);

        returndata = data;
    },
    error: function (xhRequest, ErrorText, thrownError) {
        alert("Failed to process promotion correctly, please try again");
        console.log('xhRequest: ' + xhRequest + "\n");
        console.log('ErrorText: ' + ErrorText + "\n");
        console.log('thrownError: ' + thrownError + "\n");
    }
});

请注意我如何使用本机内置于现代浏览器中的JSON.stringify方法，以确保发送到服务器的JSON正确并且所有值都已正确编码。如果您需要支持石器时代的浏览器，您可以在页面中加入json2.js脚本，这将定义JSON.stringify方法。

重要说明：绝对不会使用字符串连接来构建JSON字符串，如代码中那样。

或者，如果您不想发送JSON请求，则可以发送标准application/x-www-form-urlencoded请求：

$.ajax({ //actually approve or reject the promotion
    url: url,
    type: "POST",
    data: { 
        promotionId: data.PromotionId, 
        userId: data.UserId, 
        reasonText: data.ReasonText
    },
    success: function (data) {
        if (indicator == 'A') {
            alert('Promotion approved successfully!');
        }
        else {
            alert('Promotion rejected successfully.');
        }

        var homelink = '<%: Url.Action("Index","Home") %>';
        window.location.href = (homelink);

        returndata = data;
    },
    error: function (xhRequest, ErrorText, thrownError) {
        alert("Failed to process promotion correctly, please try again");
        console.log('xhRequest: ' + xhRequest + "\n");
        console.log('ErrorText: ' + ErrorText + "\n");
        console.log('thrownError: ' + thrownError + "\n");
    }
});

这应该以相同的方式工作，控制器操作应该能够正确绑定模型。

备注：我注意到您在成功回调中使用了以下行：returndata = data;。这让我相信你在某种程度上试图在成功回调之外使用异步AJAX请求的结果，这是不可能的。我不知道你对这个returndata变量做了什么，但我觉得这是错误的。

Answer 2

在MVC操作方法中将[ValidateAntiForgeryToken]属性与Ajax调用结合使用时，也会发生此错误。

检查一下，可能也有帮助： https://stackoverflow.com/a/60952294/315528

在jquery ajax帖子上不断收到400（Bad Request）到MVC控制器

2 个答案: