Display 3 lists as a matrix in C# and MVC 3.0

Question

I have these 3 classes:

 public class Product 
     {
            public int ProductId { get; set; }
            public int ClassId { get; set; }
            public string Name { get; set; }
            public virtual Class Class { get; set; }
        }



public class Partner
    {
        public int PartnerId { get; set; }
        public int ClassId { get; set; }     
        public string Name { get; set; }
        public virtual Class Class { get; set; }
    }



public class Price
    {
        public int PriceId { get; set; }
        public int ClassId { get; set; }
        public int ProductId { get; set; }
        public int PartnerId { get; set; }
        public float Cost { get; set; }
    }

and I have 3 lists of data:

List<Product> products; List<Partner> partners; List<Price> prices;

How can I show partners in top row, products in left column and price (if it is available for each partner and product) in cells of table in MVC View?

Answer 1

As always I would start by designing a view model that will reflect the requirements of the view:

public class MyViewModel
{
    public IEnumerable<Product> Products { get; set; }
    public IEnumerable<PartnerPricesViewModel> PartnerProductPrices { get; set; }
}

public class PartnerPricesViewModel
{
    public string PartnerName { get; set; }
    public IEnumerable<Price> Prices { get; set; }
}

and then I will populate this view model in the controller action from our domain models and pass it to the view:

public ActionResult Index()
{
    List<Product> products = ...
    List<Partner> partners = ...
    List<Price> prices = ...

    var model = new MyViewModel
    {
        Products = products,
        PartnerProductPrices =
            from partner in partners
            select new PartnerPricesViewModel
            {
                PartnerName = partner.Name,
                Prices = 
                    from product in products
                    select prices.FirstOrDefault(price => 
                        price.PartnerId == partner.PartnerId && 
                        price.ProductId == product.ProductId
                    )
            }
    };

    return View(model);
}

and finally I will have a corresponding strongly typed view to the view model:

@model MyViewModel

<table>
    <thead>
        <tr>
            <th></th>
            @foreach (var product in Model.Products)
            {
                <th>@product.Name</th>
            }
        </tr>
    </thead>
    <tbody>
        @foreach (var partner in Model.PartnerProductPrices)
        {
            <tr>
                <td>@partner.PartnerName</td>
                @foreach (var price in partner.Prices)
                {
                    <td>
                        @if (price != null)
                        {
                            @price.Cost.ToString("c")
                        }
                        else
                        {
                            // There was no price found matching this 
                            // product and partner => we display an empty cell
                            @:&nbsp;    
                        }
                    </td>
                }
            </tr>
        }
    </tbody>
</table>

Answer 2

Your prices list is very SQL friendly, but doesn't really fit the actual problem. I think your prices should be stored in a Dictionary<Tuple<Product, Partner>, Price> instead of a List<Price> .

Since this is MVC, I would use that dictionary as part of the view-model (along with the products and partners). Then displaying it as a table is going to be very straightforward.