带有别名值的LINQ to Razor View子查询

Question

Background: I have a few tables joined with the following LINQ statement:

var viewModel = new ContractorViewModel();
var Query = (from c in db.Contractors
             join cmb in db.ContractorManagedBies on c.ManagedBy equals cmb.ManagedBy
             join dc in db.DCLocMappings on c.LocationID equals dc.LocationID
             join at in db.AccountTitles on c.AccountTitleID equals at.AccountTitleID
             where dc.DeliveryCenter == location
             select new ContractorViewModel 
             { 
                 Id = cmb.ManagedBy, 
                 FullName = cmb.ManagerFirstName + ' ' + cmb.ManagerLastName 
             }).ToList();

From the first query, the row value is an integer. I want to also run a parallel LINQ query to join the values of in another table with the values of cmb.ManagerFirstName + ' ' + cmb.ManagerLastName and also show that when the same view is run. I can get most of the details data in the view when placing this at the top of the page: @model IEnumerable<DriverDatabase.Contractor> ;however, I cannot get the value of FullName in the view no matter what I try. I have tried the ViewModel approach. I thought a subquery would join the table and add the combined first name and last name values in the field from the foreach loop but that isn't the case. My question is, how to get the FullName value to the Razor View using LINQ and ASP.NET 4.5? I am accessing two data sets really but the foreach only recognizes one. Currently @Html.Display("FullName") does not return anything and there is no object for rendering FullName.

Answer 1

First, I would use double quotes (not single) in concatenation.

FullName = cmb.ManagerFirstName + " " + cmb.ManagerLastName

Then, you should be careful with string concatenation in linq to entities

If first element is null, for example, the whole result will be null.

So use a coalesce operator (I think that having it on the left part is enough)

FullName = cmb.ManagerfirstName ?? string.Empty + " " + cmb.ManagerLastName