远程验证随机抛出 "dictionary contains a null entry" 个错误

Question

当远程验证试图检查数据库中是否已存在某个值时，我遇到了这个超级恼人的错误：

The parameters dictionary contains a null entry for parameter 'gbsNumber' of non-nullable type 'System.Int32' for method 'System.Web.Mvc.JsonResult DoesGbSNumberExist(Int32)' in 'ADVWKSP.Controllers.CRMTItemsController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter. Parameter name: parameters

at System.Web.Mvc.ActionDescriptor.ExtractParameterFromDictionary(ParameterInfo parameterInfo, IDictionary`2 parameters, MethodInfo methodInfo)
at System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters)
at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters)
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<BeginInvokeSynchronousActionMethod>b__39(IAsyncResult asyncResult, ActionInvocation innerInvokeState)
at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`2.CallEndDelegate(IAsyncResult asyncResult)
at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult)
at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3d()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<>c__DisplayClass46.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3f()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass33.<BeginInvokeActionMethodWithFilters>b__32(IAsyncResult asyncResult)
at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult)
at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult)
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass21.<>c__DisplayClass2b.<BeginInvokeAction>b__1c()
at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult)

它断断续续地发生，我无法找出任何一种模式 - 它似乎完全是随机的。

它发生在我的两个字段上，这两个字段都映射到视图模型中的整数属性。

它不仅会填满我的错误日志，而且还会破坏表单，以至于提交按钮有时不起作用，这很烦人。

控制器

[HttpPost]
public JsonResult DoesGbSNumberExist(int gbsNumber)
{
    using (var db = new ADVWKSPEntities())
    {
        return Json(!db.CRMTItems.Any(i => i.GbsNumber == gbsNumber));
    }
}

ViewModel

public class CRMTItemViewModel
{
    public int Id { get; set; }

    [Required]
    [Display(Name = "Project Title")]
    [Remote("DoesProjectTitleExist", "CRMTItems", HttpMethod = "POST", 
        ErrorMessage = "Workspace for that project title already exists.")]
    public string ProjectTitle { get; set; }

    [Required]
    [Display(Name = "Project Stage")]
    public ProjectStage? ProjectStage { get; set; }

    [Required]
    [Display(Name = "CRMT Number")]
    [Remote("DoesCrmtNumberExist", "CRMTItems", HttpMethod = "POST",
        ErrorMessage = "Workspace for that CRMT number already exists.")]
    public int? CRMTNumber { get; set; }

    [Required]
    [Display(Name = "GBS Number")]
    [Remote("DoesGbSNumberExist", "CRMTItems", HttpMethod = "POST", 
        ErrorMessage = "Workspace for that GBS project number already exists.")]
    public int? GbSNumber { get; set; }

    public bool Confidential { get; set; }

    [Required]
    [Display(Name = "Project Managers")]
    public IEnumerable<string> SelectedTags { get; set; }
}

查看

@using (Ajax.BeginForm("Create", "CRMTItems", new AjaxOptions
    {
        HttpMethod = "Post",
        UpdateTargetId = "divToUpdate",
        OnBegin = "submitBegin",
        OnSuccess = "submitSuccess",
        OnFailure = "submitFailure",
        OnComplete = "submitComplete"

    }, new { @ID = "AjaxForm" }))
{
<div class="form-horizontal">
    <h4>New Project Workspace Form</h4>
    <hr />
    @Html.ValidationSummary(true, "", new { @class = "text-danger" })
    <div class="form-group">
        @Html.LabelFor(model => model.ProjectTitle, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model.ProjectTitle, new { htmlAttributes = new { @class = "form-control"} })
            @Html.ValidationMessageFor(model => model.ProjectTitle, "", new { @class = "text-danger" })
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.ProjectStage, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EnumDropDownListFor(model => model.ProjectStage, new { @class = "form-control"})
            @Html.ValidationMessageFor(model => model.ProjectStage, "", new { @class = "text-danger" })
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.CRMTNumber, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model.CRMTNumber, new { htmlAttributes = new { @class = "form-control"} })
            @Html.ValidationMessageFor(model => model.CRMTNumber, "", new { @class = "text-danger" })
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.GbSNumber, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model.GbSNumber, new { htmlAttributes = new { @class = "form-control"} })
            @Html.ValidationMessageFor(model => model.GbSNumber, "", new { @class = "text-danger" })
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(model => model.Confidential, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.CheckBoxFor(model => model.Confidential, new { @class = "form-control", @style = "height:17px;" })
            @Html.ValidationMessageFor(model => model.Confidential, "", new { @class = "text-danger" })
        </div>
    </div>

    <div class="form-group">
        @Html.LabelFor(model => Model.SelectedTags, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.HiddenFor(m => m.Id)
            @Html.ListBoxFor(m => m.SelectedTags, new SelectList(users, "UserName", "DisplayName"), new { @class = "teamSelecter", name = "states[]", multiple = "multiple", style = "display:none; width:100%;"})
            @Html.ValidationMessageFor(model => model.SelectedTags, "", new { @class = "text-danger" })
            <p id="pmWarning" class="text-danger" hidden>Please select one or more project managers</p>
        </div>
    </div>

    <br />
    <button id="formSubmit" class="btn btn-default btn-lg pull-right" type="submit" value="submit">Submit</button>
    <div class="loader pull-right" hidden></div>
</div>
}

Answer 1

我将参数类型更改为 int?，此后没有看到错误，所以希望问题已解决，但我们会看到。

更新控制器：

[HttpPost]
public JsonResult DoesGbSNumberExist(int? gbsNumber)
{
    using (var db = new ADVWKSPEntities())
    {
        return (gbsNumber == null) ? Json(false) : Json(!db.CRMTItems.Any(i => i.GbsNumber == gbsNumber));
    }
}

Answer 2

您的视图模型将整数值定义为可为空的 int int?。可为空的 int 只有在包含值时才能与 int 进行比较。

您的线路：

return Json(!db.CRMTItems.Any(i => i.GbsNumber == gbsNumber));

应测试空值：

return Json(!db.CRMTItems.Any(i => (i.GbsNumber ?? 0) == gbsNumber));

用 GbsNumber 不包含的值替换零。

远程验证随机抛出 "dictionary contains a null entry" 个错误

Remote validation randomly throws "dictionary contains a null entry" errors

c#

ajax

asp.net-mvc

remote-validation