Displaying a List in a Partial View Using a ViewModel in MVC

In modern web applications, it's common to use partial views to encapsulate and reuse view logic. When working with partial views in an MVC-based project, you might encounter scenarios where you need to display a list of items dynamically. This can become tricky if the data structure in your ViewModel isn't set up to support iteration.

In this blog post, we'll walk through a practical example of how to structure your ViewModel to facilitate listing items in a partial view. We'll cover the necessary changes to the ViewModel, controller, and the views to ensure that your data is displayed correctly and efficiently. By the end, you'll have a clear understanding of how to seamlessly integrate dynamic lists into your MVC partial views.

Since NewinformationVm contains individual properties (person and student) and not a collection, iterating over NewinformationVm directly isn't valid. If you want to display a list of items, your ViewModel needs to contain a collection of items you can iterate over.

Here’s a way to structure your ViewModel to support listing and iteration in the partial view:

ViewModel with a Collection

public class NewInformationVm
{
    public int Id { get; set; }
    public Person Person { get; set; } // Person model
    public Student Student { get; set; } // Student model
    public List<Item> Items { get; set; } // Collection of items

    public NewInformationVm()
    {
        Person = new Person();
        Student = new Student();
        Items = new List<Item>();
    }
}

public class Item
{
    public int ItemId { get; set; }
    public string ItemName { get; set; }
    // other properties...
}

Controller

Make sure your controller is populating the Items collection appropriately.

public ActionResult Create()
{
    var viewModel = new NewInformationVm
    {
        Items = GetItems() // Fetch or initialize your list of items here
    };
    return View(viewModel);
}

private List<Item> GetItems()
{
    // Logic to fetch or create items
    return new List<Item>
    {
        new Item { ItemId = 1, ItemName = "Item 1" },
        new Item { ItemId = 2, ItemName = "Item 2" }
        // Add more items...
    };
}

Partial View

Update your partial view to iterate over the Items collection.

@model myprojectname.ViewModels.NewInformationVm

<h3>Item List</h3>
@if (Model.Items != null && Model.Items.Any())
{
    <ul>
    @foreach (var item in Model.Items)
    {
        <li>@item.ItemName</li>
    }
    </ul>
}
else
{
    <p>No items available.</p>
}

Main View

Ensure your main view is including the partial view correctly.

@model myprojectname.ViewModels.NewInformationVm

<!-- Main view content for creating records -->
@Html.Partial("_PartialViewName", Model)

By adding a collection property (Items) to your ViewModel and ensuring the partial view iterates over this collection, you should be able to list the records without encountering the "model does not exist" error.