convert model to viewmodel [duplicate]

问题:

This question already has an answer here:

• Where to convert business model to view model? 2 answers

I have a table name "Product" and another table name "category". Product table has 'productID', 'productName' and 'CategoryID'. Category table has 'categoryID' and 'categoryName'.

My target is to display a list of products with category. The list will contain 'product id', 'product name' and 'category name'.

I have created a viewmodel. the code is

public int prodID{get;set;}
public int prodName{get;set;}
public int catName{get;set;}

In my controller, I have:

var query= from p in dc.Product
                      select new {p.ProductID,p.ProductName,p.Category1.CategoryName };
var prod = new ProductIndexViewModel()
        {
            ProductList=query //this line is problematic !!it says an explicit conversion exists....
        };
        return View(prod);

How would I write my controller code so that it matches with the viewmodel??

回答1:

Maybe you will use your view model class directly:

       var query = from p in dc.Product
                    select new ProductIndexViewModel() { 
                        prodID = p.ProductID, 
                        prodName = p.ProductName, 
                        catName = p.Category1.CategoryName 
                    };

        List<ProductIndexViewModel> productForView = query.ToList();

回答2:

You can use AutoMapper instead of rewriting properties from db model.

var viewModel = new ProductIndexViewModel()
{  
    ProductList = dc.Product.ToList().Select(product => Mapper.Map<Product, ProductViewModel>(product));
}

回答3:

Should prodName and catName be strings?

Also, why not just do this:

var viewModel = dc.Product
    .ToList()
    .Select(x => new ProductIndexViewModel { prodID = x.ProductId, ... }

return View(viewModel);