MVC: Dictionary requires a model item of type 'System.Collections.Generic.IEnumerable`1

问题

I am getting this error and I'm not sure if I am able to do this, here is my code..

Application controller

public ActionResult AppView()
{
    List<Application> apps;
    using (ISiteDbContext context = _resolver.GetService<ISiteDbContext>())
    {
        apps = context.Applications.ToList();
    } 
    return PartialView("AppView", apps.OrderBy(a => a.Name).ToList());
}

Render partial - this is within a view which is in the home controller.

@{Html.RenderPartial("~/Views/Application/AppView.cshtml", new Example.Services.DAL.Application());}

and my application view

@model IEnumerable<Example.Services.DAL.Application>

@{
    ViewBag.Title = "Applications";
}

<h2>Applications</h2>

<p>
    @Html.ActionLink("Add New Application", "Create")
</p>
<table>
    <tr>
        <th>
            @Html.DisplayNameFor(model => model.Name)
        </th>
        <th></th>
    </tr>

    @foreach (var item in Model)
    {
    <tr>
        <td>
            @Html.DisplayFor(modelItem => item.Name)
        </td>
        <td>
            @Html.ActionLink("Edit", "Edit", new { id = item.ID }) |
            @Html.ActionLink("Details", "Details", new { id = item.ID }) |
            @Html.ActionLink("Delete", "Delete", new { id = item.ID })
        </td>
    </tr>
    }

</table>

full error message:

The model item passed into the dictionary is of type 'Example.Services.DAL.Application', but this dictionary requires a model item of type 'System.Collections.Generic.IEnumerable`1[Example.Services.DAL.Application]'.

回答1:

As error states you are passing a wrong type. Change

@{Html.RenderPartial("~/Views/Application/AppView.cshtml", new Example.Services.DAL.Application());}

to:

@{Html.RenderPartial("~/Views/Application/AppView.cshtml", new List<Example.Services.DAL.Application> { new Example.Services.DAL.Application() });}

回答2:

Your AppView.cshtml is bind to strongly type of @model IEnumerable<Example.Services.DAL.Application> and while calling this view you are passing @{Html.RenderPartial("~/Views/Application/AppView.cshtml", new Example.Services.DAL.Application());}

It should be the list object. You must pass list of Example.Services.DAL.Application()

Change your

@{Html.RenderPartial("~/Views/Application/AppView.cshtml", new Example.Services.DAL.Application());}

@{Html.RenderPartial("~/Views/Application/AppView.cshtml", new List<Example.Services.DAL.Application> { new Example.Services.DAL.Application() });}

回答3:

your code is looking for a Ienumerable because what you pass to your partial view must be the same as what is in your view so try to change the first line of your application view to

@model Example.Services.DAL.Application

it worked for me hopefully it was of good use to you as well :D

回答4:

In order to use sorting on a collection of (custom) Objects, you need a method for sorting it. Usually, this is accomplished by inheriting the "IComparable" interface. In your Object class, you then need a method "Compare" to determine the method of comparing the instances of your Objects for sorting (I use "Date" in my project).

To recap:

You use this in your Application Controller:

return PartialView("AppView", apps.OrderBy(a => a.Name).ToList());

But in order to actually sort (or in this case OrderBy), you need a method in your "Application" class that compares the instances in the list to sort them. This is done using the "Compare" method: