超文本标记语言beginForm post List<的空值;在asp.net - mvc5中通过jQuery Aj

对不同的表单使用相同的控制器post动作。你的动作更新模型(实体列表)只有实体出现在第一个位置。你的模型有一个列表[entity0, entity1]，但在表单视图中，你删除了entity0，因为你只从模型列表绑定了一个entity1。

这里有两种方法:

让post controller动作更通用

    public ActionResult EditEmergencyContact (List<EmergencyContact> _emergencyContactModel)
            {
                try
                {
                    if (_emergencyContactModel != null && _emergencyContactModel.Count() > 0)
                    {
                        if (ModelState.IsValid)
                        {
                            bool validation = true;
                            for (int i = 1; i < _emergencyContactModel.Count(); i++)
                            {
                                if (_emergencyContactModel[i].EmergencyContactID != null)
                                {
                                    int _entityID = _studentProfileServices.EditEmergencyContactByStudentID(
                                    new EmergencyContact
                                    {
                                        EmergencyContactID = _emergencyContactModel[i].EmergencyContactID,
                                        StudentID = _emergencyContactModel[i].StudentID,
                                        NameOfContact = _emergencyContactModel[i].NameOfContact,
                                        Relationship = _emergencyContactModel[i].Relationship,
                                        Telephone = _emergencyContactModel[i].Telephone,
                                        Mobile = _emergencyContactModel[i].Mobile,
                                        Address = _emergencyContactModel[i].Address
                                    });
                                    if (_entityID == 0)
                                    {
                                        validation = false;
                                        break;
                                    }
                                }
                            }
                            if (validation)
                            {
                                return Json(new { Response = "Success" });
                            }
                            else
                            {
                                return Json(new { Response = "Error" });
                            }
                        }
                        else
                        {
                            return Json(new { Response = "Invalid Entry" });
                        }
                    }
                    else
                    {
                        return Json(new { Response = "Error! In Updating Record" });
                    }
                }
                catch (DataException ex)
                {
                    ModelState.AddModelError("", "Unable To Edit Emergency Contact" + ex);
                }
                return RedirectToAction("MyProfile", "StudentProfile");
            }

选项2，不传递模型空实体到控制器，隐藏在表单中的值:

@using (Html.BeginForm("EditEmergencyContact", "StudentProfile", FormMethod.Post, new { id = "EditNo2EmergencyContactForm" }))
{
  @Html.AntiForgeryToken()
<div class="form-horizontal">
    <h4>Emergency Contact 2</h4>
    <hr />
    @Html.ValidationSummary(true, "", new { @class = "text-danger" })
    @* here you pas List 0  model recieved value and viceversa if you edit model[0]*@
    @Html.HiddenFor(model => model[0].EmergencyContactID)
    @Html.HiddenFor(model => model[0].StudentID)
    @Html.HiddenFor(model => model[0].NameOfContact)
    @Html.HiddenFor(model => model[0].Relationship)
    @Html.HiddenFor(model => model[0].Telephone)
    @Html.HiddenFor(model => model[0].Mobile)
    @Html.HiddenFor(model => model[0].Address)
    @Html.HiddenFor(model => model[0].Address)
    @Html.HiddenFor(model => model[1].EmergencyContactID)
    <div class="form-group">
        @Html.LabelFor(model => model[1].StudentID, "StudentID", htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model[1].StudentID, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model[1].StudentID, "", new { @class = "text-danger" })
        </div>
    </div>
    <div class="form-group">
        @Html.LabelFor(model => model[1].NameOfContact, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model[1].NameOfContact, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model[1].NameOfContact, "", new { @class = "text-danger" })
        </div>
    </div>
    <div class="form-group">
        @Html.LabelFor(model => model[1].Relationship, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model[1].Relationship, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model[1].Relationship, "", new { @class = "text-danger" })
        </div>
    </div>
    <div class="form-group">
        @Html.LabelFor(model => model[1].Telephone, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model[1].Telephone, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model[1].Telephone, "", new { @class = "text-danger" })
        </div>
    </div>
    <div class="form-group">
        @Html.LabelFor(model => model[1].Mobile, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model[1].Mobile, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model[1].Mobile, "", new { @class = "text-danger" })
        </div>
    </div>
    <div class="form-group">
        @Html.LabelFor(model => model[1].Address, htmlAttributes: new { @class = "control-label col-md-2" })
        <div class="col-md-10">
            @Html.EditorFor(model => model[1].Address, new { htmlAttributes = new { @class = "form-control" } })
            @Html.ValidationMessageFor(model => model[1].Address, "", new { @class = "text-danger" })
        </div>
    </div>
    <div class="form-group">
        <div class="col-md-offset-2 col-md-10">
            <input type="submit" value="Save" class="btn btn-default" />
        </div>
    </div>
 </div>
}

从列表中更新两个实体的控制器:

int _entityID_0 = _studentProfileServices.EditEmergencyContactByStudentID(
new EmergencyContact
{
    EmergencyContactID = _emergencyContactModel[0].EmergencyContactID,
    StudentID = _emergencyContactModel[0].StudentID,
    NameOfContact = _emergencyContactModel[0].NameOfContact,
    Relationship = _emergencyContactModel[0].Relationship,
    Telephone = _emergencyContactModel[0].Telephone,
    Mobile = _emergencyContactModel[0].Mobile,
    Address = _emergencyContactModel[0].Address
});
int _entityID_1 = _studentProfileServices.EditEmergencyContactByStudentID(
new EmergencyContact
{
    EmergencyContactID = _emergencyContactModel[1].EmergencyContactID,
    StudentID = _emergencyContactModel[1].StudentID,
    NameOfContact = _emergencyContactModel[1].NameOfContact,
    Relationship = _emergencyContactModel[1].Relationship,
    Telephone = _emergencyContactModel[1].Telephone,
    Mobile = _emergencyContactModel[1].Mobile,
    Address = _emergencyContactModel[1].Address
});
if (_entityID_0 != 0 && _entityID_1 != 0)
{
    return Json(new { Response = "Success" });
}
else
{
    return Json(new { Response = "Error" });
}

你的方法很糟糕，你应该逐个更新地址，而不是一个复杂的地址列表。