Error creating RenderPartialAsync, problem in controller? - asp.net

Question

There is an Index controller, in it I associate data from a database with a modelview and my View collects user data and displays it. And accordingly below I will attach PartialView
public class CustomerController : Controller
{
private ICustomerRepository _customerRepository;
public CustomerController(ICustomerRepository customerRepository)
{
_customerRepository = customerRepository;
}
[HttpGet]
public IActionResult Index()
{
IEnumerable<CustomerViewModel> customers =
_customerRepository.GetAllCustomers().Select(s => new
CustomerViewModel
{
CustomerId = s.CustomerId,
Name = s.Name,
Adress = s.Adress
});
return View("Index", customers);
}
[HttpGet]
public IActionResult Create()
{
return Redirect("Index");
}
}
#model IEnumerable<CustomerViewModel>
<h2>Create Customer</h2>
#{
await Html.RenderPartialAsync("Create");
}
<table class="table">
#Html.DisplayNameFor(model => model.Name)
#foreach (var item in Model)
{
#Html.DisplayFor(modelItem => item.Name)
}
</table>
This is PartialView itself:
#model CustomerViewModel
<div class="col-md-4">
<form asp-action="Create" asp-controller="Customer">
<div class="form-group">
<label asp-for="Name" class="control-label"></label>
<input type="text" asp-for="Name" class="form-control" />
</div>
When the application starts, an error occurs:
InvalidOperationException: The model item passed into the
ViewDataDictionary is of type 'System.Linq.Enumerable+SelectEnumerableIterator`
2[Store.DAL.Entity.Customer,Store.Web.ViewModels.CustomerViewModel]', but this
ViewDataDictionary instance requires a model item of type 'Store.Web.ViewModels.
CustomerViewModel
If partialView is put on a separate page, just to create a link to the View, everything will be displayed and there will be no error.
Maybe it's all about how I override the data in the Controller for customerViewModel?
Who dealt with this?

Answer 1

What happens
In your code, you're not giving your View a model it expects.
If you use Html.RenderPartialAsync(viewName) you are automatically passing the entire model from the main view to the partial. Since the main view has model type of IEnumerable<CustomerViewModel> - that's what's passed to your partial view.
Solutions
Use separate page for creating objects instead of reusing the same page for displaying existing ones
Make your model more complex so that it can be used for both views and use an overload of Html.RenderPartialAsync(string viewName, object model) to pass the model properly.
For solution #2 the example code could be:
New class
public class CustomerListViewModel
{
IEnumerable<CustomerViewModel> existingCustomers;
CustomerViewModel newCustomer;
}
Controller
[HttpGet]
public IActionResult Index()
{
IEnumerable<CustomerViewModel> customers =
_customerRepository.GetAllCustomers().Select(s => new
CustomerViewModel
{
CustomerId = s.CustomerId,
Name = s.Name,
Adress = s.Adress
});
CustomerListViewModel model = new CustomerListViewModel
{
existingCustomers = customers.AsEnumerable();
newCustomer = new CustomerViewModel();
}
return View("Index", model);
}
Main view
#model CustomerListViewModel
<h2>Create Customer</h2>
#{
await Html.RenderPartialAsync("Create", Model.newCustomer);
}
<table class="table">
#foreach (var item in Model.existingCustomers)
{
<tr>
<td>#Html.DisplayFor(item => item.Name)</td>
</tr>
}
</table>