发行保存编辑后的数据：DDL值不能为空 [英] Issue Saving Edited Data: DDL Value can not be null
问题描述
我有保存编辑的字段在我的MVC项目的问题。当我点击提交按钮，我得到一个错误
I am having an issue with saving the edited fields in my MVC project. When I click the submit button I get an error
值不能为空。
参数名：项目
说明：执行当前Web请求的执行过程中发生未处理的异常。请查看有关错误的详细信息的堆栈跟踪以及它起源于code。
Value cannot be null. Parameter name: items Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
异常详细信息：System.ArgumentNullException：值不能为空。
参数名称：项目
Exception Details: System.ArgumentNullException: Value cannot be null. Parameter name: items
源错误：
63号线：
64号线：
65号线：@ Html.DropDownListFor（型号=> model.EventTypeID，新的SelectList（ViewBag.EventTypes，EventTypeID，EventType1），选择）
66号线：
第67行：
Line 63: Line 64: Line 65: @Html.DropDownListFor(model => model.EventTypeID, new SelectList(ViewBag.EventTypes, "EventTypeID", "EventType1"), "Choose") Line 66: Line 67:
我尝试过的一些事情，我已经看到了互联网上，但它似乎并没有为我做任何事情:(帮助将AP preciated谢谢！
I have tried some things that I have seen on the internet but it doesn't seem to be doing anything for me :( Help would be appreciated thank you!
这是我的控制器当我把一个破发点这里从来没有触发。
this is my controller When I put a break point here it never triggers.
[HttpPost]
public ActionResult IndexPST(Event_Setup es)
{
db.Event_Setup.Add(es);
db.SaveChanges();
return View("Index",es);
}
这是我的看法。
@model DixonGroupInc.Models.Event_Setup
<link href="~/Content/EventManagement.css" rel="stylesheet" />
@using (Html.BeginForm("IndexPST", "EventManagement", FormMethod.Post))
{
@Html.AntiForgeryToken()
@Html.ValidationSummary(true)
<div id="cntr">
<div id="emLoc">
<table id="ldTbl">
<thead>
<tr>
<th class="ln">
<img src="~/Images/4.gif" />
</th>
<th>
<img src="~/Images/5.gif" />
</th>
<th>
<img src="~/Images/5.gif" />
</th>
<th>
<img src="~/Images/5.gif" />
</th>
<th>
<img src="~/Images/5.gif" />
</th>
</tr>
</thead>
<tbody>
<tr>
<td class="chosen space">EventMetadata
</td>
<td class="space">Client / Vendor
</td>
<td class="space">Venu info
</td>
<td class="space">Sponsored Participants
</td>
<td class="space">Event Services
</td>
</tr>
</tbody>
</table>
</div>
<div id="emSetup">
Setup Meeting
</div>
<div id="emTable">
<table class="myTbl">
<tr>
<td class="lblEvent clm1">
@Html.Label("Event Type")
</td>
<td class="clm2">
@Html.DropDownListFor(model => model.EventTypeID, new SelectList(ViewBag.EventTypes, "EventTypeID", "EventType1"), "Choose")
</td>
<td class="clm3">
@{Html.RenderAction("EventType", "EventManagement");}
</td>
</tr>
<tr class="rows">
<td class="lblEvent clm1">
@Html.Label("Event Title")
</td>
<td class="clm2">
@Html.EditorFor(model => model.EventTitle)
@Html.ValidationMessageFor(model => model.EventTitle)
</td>
</tr>
<tr>
<td class="lblEvent clm1">
@Html.Label("Event Identifier")
</td>
<td class="clm2">
@Html.EditorFor(model => model.EventIdentifier)
@Html.ValidationMessageFor(model => model.EventIdentifier)
</td>
</tr>
</table>
<table class="dateTbl">
<tr class="rows">
<td class="lblEvent clm1">
@Html.Label("Event Date From")
</td>
<td class="clm2">
@Html.TextBoxFor(model => model.EventDateFrom, new { @class = "dateFrom" })
@Html.ValidationMessageFor(model => model.EventDateFrom)
</td>
<td class="lblEvent">
@Html.Label("To")
</td>
<td class="clm4">
@Html.TextBoxFor(model => model.EventDateTo, new { @class = "dateTo" })
@Html.ValidationMessageFor(model => model.EventDateTo)
</td>
</tr>
</table>
<table class="myTbl">
<tr>
<td class="lblEvent clm1">
@Html.Label("Event Description")
</td>
<td class="clm2">
@Html.TextAreaFor(model => model.EventDescription, new
{
id = "taED"
})
<div>
<span id="charLeft2"></span>characters remaining.
</div>
@Html.ValidationMessageFor(model => model.EventDescription)
</td>
</tr>
<tr class="rows">
<td class="lblEvent clm1">
@Html.Label("Custom Message")
</td>
<td class="clm2">
@Html.TextAreaFor(model => model.CustomMessage, new
{
id = "taCM"
})
<div>
<span id="charLeft1"></span>characters remaining.
</div>
@Html.ValidationMessageFor(model => model.CustomMessage)
</td>
</tr>
<tr>
<td class="lblEvent clm1">
@Html.Label("Instructions")
</td>
<td class="clm2">
@Html.TextAreaFor(model => model.Instructions, new
{
id = "taInstrct"
})
<div>
<span id="charLeft"></span>characters remaining.
</div>
@Html.ValidationMessageFor(model => model.Instructions)
</td>
</tr>
</table>
<table class="myTbl">
<tr class="rows">
<td>
@{Html.RenderAction("AddTrack", "EventManagement");}
</td>
</tr>
<tr>
<td>
@{Html.RenderAction("EventTrack", "EventManagement");}
</td>
</tr>
</table>
<table class="myTbl">
<tr class="rows">
<td class="lblEvent clm1">
@Html.Label("CFP Pocess")
</td>
<td class="clm2">
@Html.RadioButtonFor(model => model.CFPRequired, "true") Yes
</td>
<td class="clm3">
@Html.RadioButtonFor(model => model.CFPRequired, "false") No
</td>
</tr>
</table>
</div>
<div id="emSubmit">
<input type="submit" value="Save & Next" id="submit" />
</div>
</div>
}
推荐答案
Viewbag可能不可靠所以一般不建议通过您的下拉通过viewbag列表数据。我建议将其添加到您的视图模型来代替。在你Event_Setup类请确保您有
Viewbag can be unreliable so generally it isn't recommended to pass your drop down list data through the viewbag. I would recommend adding it to your view model instead. In your Event_Setup class make sure that you have
public int EventTypeID { get; set; }
和
public List<SelectListItem> EventTypeList { get; set; }
您的控制器上让你可以设置EventTypeID设置的下拉默认下来，你的控制器应该有类似
on your controller get you can set EventTypeID to set a default on the drop down so your controller should have something like
Event_Setup es = new Event_Setup();
es.EventTypeID = //default value if you want;
es.EventTypeList = //Method call here where List<SelectListItem> is returned with your event list
然后在您的视图中，可以改变你的下拉菜单
then on your view you can change your drop down to
@Html.DropDownListFor(x => x.EventTypeID, Model.EventTypeList)
这篇关于发行保存编辑后的数据：DDL值不能为空的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
