"InvalidDataException: Form value count limit 1024 exceeded." 当 post 在 asp.net 核心中从视图到控制器的值超过 1000 个时，模型为空

Question

我正在尝试根据角色向 selected 候选人发送批量电子邮件。当我 selected 有限的选项然后模型正确通过时，但是一旦我 select 来自 multiselect 下拉列表的 1000 个选项和来自模型的 post 通过 null.

非常奇怪，有什么原因吗？

电子邮件模板视图模型

public class EmailTemplateViewModel
{
    public EmailTemplateViewModel()
    {
        LstEmailTemplate = new List<EmailTemplateModel>();
        
        SendEmailModel = new SendEmailModel();
    }
    public List<EmailTemplateModel> LstEmailTemplate { get; set; }
   
    public Pager Pager { get; set; }
    public SendEmailModel SendEmailModel { get; set; }
}

查看

    @model Practise.Models.EmailTemplateViewModel
@using (Html.BeginForm("SentBulkEMail", "EmailTemplate", FormMethod.Post, new { @class = "form-horizontal" }))
                {
                    @Html.HiddenFor(x => x.SendEmailModel.EmailTemplateId, new { id = "hdnEmailTemplateId" })
                    <div class="form-group">
                        <label class="col-lg-2 control-label">User Type</label>
                        <div class="col-lg-10">
                            @Html.DropDownListFor(x => x.SendEmailModel.Roles, new SelectList(Roles, "Value", "Text"), new { id = "Roles", @class = "form-control select2", multiple = "multiple", @required = "required" })
                        </div>
                    </div>
                    <div class="form-group">
                        <label class="col-lg-2 control-label">Recipients</label>
                        <div class="col-lg-10">
                            @Html.DropDownListFor(x => x.SendEmailModel.Recipient, new SelectList(ViewBag.Recipient as IEnumerable<SelectListItem>), "", new { id = "Recipients", multiple = "multiple", @required = "required", @class = "form-control" })
                        </div>
                    </div>
                    <div class="form-group">
                        <label class="col-lg-2 control-label">Subject</label>
                        <div class="col-lg-10">
                            @Html.TextBoxFor(x => x.SendEmailModel.Subject, new { id = "subject", @class = "form-control", @required = "required" })
                        </div>
                    </div>
                    <div class="form-group">
                        <label class="col-lg-2 control-label">Message</label>
                        <div class="col-lg-10">
                            @Html.TextAreaFor(x => x.SendEmailModel.Description, new { id = "hdndescription", @class = "form-control", @required = "required" })
                        </div>
                    </div>
                    <div class="form-group">
                        <div class="col-lg-offset-2 col-lg-10">
                            <button class="btn btn-primary" type="submit">Send</button>
                            <button class="btn btn-danger" type="button" data-dismiss="modal">Close</button>
                        </div>
                    </div>
                }

控制器

[HttpPost]
        public async Task<IActionResult> SentBulkEMail(EmailTemplateViewModel emailTemplateViewModel)
        {
            CustomResponseModel response = new CustomResponseModel();
            response = await _emailTemplateService.SentBulkEmail(Request);
            if (response.IsSuccess)
            {
                TempData[Constant.Success] = response.Message;
            }
            else
            {
                TempData[Constant.Error] = response.Message;
            }
            return RedirectToAction("List");
        }

你可以从下图中得到更好的想法：

第一个 select multi select 只有 4 个选项

控制器当select 4个选项

第 2 select 超过 1000

控制器当我select超过1000个选项

Answer 1

终于找到答案了

默认请求值限制为 1024 .

为此，我们需要使用 RequestFormLimits 属性设置请求限制，如下所示：

[HttpPost]
[RequestFormLimits(ValueCountLimit = Int32.MaxValue)]
public async Task<IActionResult> SentBulkEMail(SendEmailModel emailModel)
{
}

添加此属性后 ValueCountLimit 允许请求值高达 Int32.MaxValue 或者您可以根据您的要求进行设置。

"InvalidDataException: Form value count limit 1024 exceeded." 当 post 在 asp.net 核心中从视图到控制器的值超过 1000 个时，模型为空

"InvalidDataException: Form value count limit 1024 exceeded." model null when post more then 1000 values from view to controller in asp.net core

c#

bootstrap-multiselect

asp.net-core

asp.net-core-3.1