c# - 从 MVC HttpPost 将错误返回给 jQuery

Question

我在 Controller 中有一个如下所示的方法:

[HttpPost]
public void UnfavoriteEvent(int id)
{
    try
    {
        var rows = _connection.Execute("DELETE UserEvent WHERE UserID = (SELECT up.UserID FROM UserProfile up WHERE up.UserName = @UserName) AND EventID = @EventID",
            new { EventID = id, UserName = User.Identity.Name });
        if (rows != 1)
        {
            Response.StatusCode = 500;
            Response.Status = "There was an unknown error updating the database.";
            //throw new HttpException(500, "There was an unknown error updating the database.");
        }
    }
    catch (Exception ex)
    {
        Response.StatusCode = 500;
        Response.Status = ex.Message;
        //throw new HttpException(500, ex.Message);
    }
}

如您所见，我尝试了几种不同的方法来恢复此错误。在 JavaScript 中，我有以下 block 来调用此方法:

var jqXHR;
if (isFavorite) {
    jqXHR = $.ajax({
        type: 'POST',
        url: '/Account/UnfavoriteEvent',
        data: { id: $("#EventID").val() }
    });
}
else {
    jqXHR = $.ajax({
        type: 'POST',
        url: '/Account/FavoriteEvent',
        data: { id: $("#EventID").val() }
    });
}

jqXHR.error = function (data) {
    $("#ajaxErrorMessage").val(data);
    $("#ajaxError").toggle(2000);
};

现在，我想要做的是将发生的错误返回给 jqXHR.error 函数，以便我可以正确处理它。

目前未注释的代码会抛出一个异常，说明我在 Status 中放置的文本是不允许的，注释代码实际上返回标准错误页面作为响应(这并不奇怪).

所以，我有几个问题:

1. 如何正确抛出错误？
2. Response.Status 属性有什么作用？

谢谢大家!

Answer 1

您将能够从 javascript 端获取响应状态，执行以下操作:

$.ajax({
    type: 'POST',
    url: '/Account/UnfavoriteEvent',
    data: { id: $("#EventID").val() },
    success: function(data, textStatus, jqXHR) {
        // jqXHR.status contains the Response.Status set on the server
    },
    error: function(jqXHR, textStatus, errorThrown) {
        // jqXHR.status contains the Response.Status set on the server
    }});

如您所见，您必须将 error 函数传递给 ajax 函数...在您的示例中，您将函数设置为 jqXHR 的错误 属性完全无效。

关于 ajax 事件的文档

• jQuery - Ajax Events

jQuery 文档说错误字符串将出现在 errorThrown 参数中。

不要使用 Response

相反，您应该返回 HttpStatusCodeResult:

[HttpPost]
public void UnfavoriteEvent(int id)
{
    try
    {
        var rows = _connection.Execute("DELETE UserEvent WHERE UserID = (SELECT up.UserID FROM UserProfile up WHERE up.UserName = @UserName) AND EventID = @EventID",
            new { EventID = id, UserName = User.Identity.Name });
        if (rows != 1)
        {
            return new HttpStatusCodeResult(500, "There was an unknown error updating the database.");
        }
    }
    catch (Exception ex)
    {
        return new HttpStatusCodeResult(500, ex.Message);
    }
}