参数词典共包含参数无效项 [英] The parameters dictionary contains a null entry for parameter

问题描述

<%using (Html.BeginForm("OrderDevice", "ImportXML", FormMethod.Post))
{ %>

<table id="OrderDevices" class="data-table">
    <tr>

        <th>
            DeviceId
        </th>
        <th>
            Id
        </th>
        <th>
            OrderId
        </th>
    </tr>

<% foreach (var item in Model) { %>

    <tr>

        <td>
            <input readonly="readonly" class="" id="DeviceId" type="text" 
                name="<%= Html.Encode(item.DeviceId) %>"  
                value="<%= Html.Encode(item.DeviceId) %>" style="width: 61px" />
        </td>
        <td>
            <input readonly="readonly" class="" id="c" type="text" 
                name= "<%= Html.Encode(item.Id) %>"  value="
    <%= Html.Encode(item.Id) %>" 
                style="width: 50px" />      
        </td>
        <td>
            <input readonly="readonly" class="" id="OrderId" type="text" 
                name= " <%= Html.Encode(item.OrderId) %>"  
                value="<%= Html.Encode(item.OrderId) %> " style="width: 49px" /> 
        </td>
    </tr>

<% } %>

</table>

<input type="submit" value="Create"/>
<%} %>

我的控制器动作：

My controller action:

    [AcceptVerbs(HttpVerbs.Post)]
    public ActionResult OrderDevice(int id)
    {   
        try
        {
            // TODO: Add insert logic here        
            orderdevice ord = new orderdevice();
            ord.Id = System.Convert.ToInt32(Request.Form["Id"]);
            ord.OrderId = System.Convert.ToInt32(Request.Form["OrderId"]);
            ord.DeviceId = System.Convert.ToInt32(Request.Form["DeviceId"]);

            XMLEntities.AddToorderdevice(ord);
            XMLEntities.SaveChanges();
            return RedirectToAction("Index");
        }
        catch
        {
            return View("Index");
        }
    }

在后一种形式我有这样的错误：参数词典共包含参数非可空类型'System.Int32'的'身份证'的方法无效项System.Web.Mvc.ActionResult OrderDevice（Int32）已在MvcKVteam.Controllers.ImportXMLController。一个可选参数必须是引用类型，可空类型，或声明为可选参数。
参数名：参数

When post a form I have this error: The parameters dictionary contains a null entry for parameter 'id' of non-nullable type 'System.Int32' for method 'System.Web.Mvc.ActionResult OrderDevice(Int32)' in 'MvcKVteam.Controllers.ImportXMLController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter. Parameter name: parameters

如何解决它？

推荐答案

首先，我会建议你使用MVC的参数自动处理，而不是ofpulling出来请求自己。您的控制器动作有一个ID参数，这似乎去理会 - 使用和添加其他类似获得的输入参数

First, I would suggest you use MVC's automatic handling of parameters instead ofpulling them out of the Request yourself. Your controller action has an id parameter which seems to go ignored - use that and add others like it to get the input parameters.

其次，你的HTML看起来有点假。您使用的设备ID，产品ID和订单ID的值的作为输入元素的名称的。这将意味着，而不必的DeviceID = 123安培;的itemId = 456安培;订单ID = 789 你得到 123 = 123安培; 456 = 456安培; 789 = 789 这是不是很实用！尝试改变输入字段是这样的：

Secondly, your HTML looks a bit off. You're using device ID, item ID and order ID values as the input element names. This will mean that instead of having deviceId=123&itemId=456&orderId=789 you're getting 123=123&456=456&789=789 which isn't very useful! Try changing the input fields to something like:

<input ... name="deviceId" value="<%= Html.Encode(item.DeviceId) %>" ... />

您可以再有一个参数caled DEVICEID 在你的控制器是这样的：

You can then have a parameter caleddeviceId in your controller like this:

public ActionResult OrderDevice(int deviceId, int itmId, int orderId)
{
    // ...
}

这样做，这样，你就不会定义使用的Request.Form [...]自己的。

Doing it this way, you won't ned to use Request.Form[...] yourself at all.

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