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How to type cast in MVC 4?

This is the case I'm facing:

I do have 3 controllers as following: a) MetricController b) CategoryController c) NavController

Before I go further, I better to share that I have a simple layout on View (HTML page) which consists of a column (on left) representing categories and on right portion of page I have to show a set of information. The information has to change base on selected category (report type) on left column.

MetricController is responsible to retrieve some information from a table (Metrics table) and it is something:

   public class Metric  {   //just a class for IIS log
        public int Id { get; set; }
        public string date { get; set; }
        public string time { get; set; }
        public string c_ip { get; set; }
        public string cs_username { get; set; }
        public string s_sitename { get; set; }
        public string s_computername { get; set; }
        public string s_ip { get; set; }
        AND MORE...

    }

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public class MetricController : Controller {
        private IMetricRepository repository;

        public MetricController(IMetricRepository metricRepository) {
            this.repository = metricRepository;
        }

        public ViewResult List() {

            MetricsListViewModel model = new MetricsListViewModel {
                Metrics = repository.Metrics
                .OrderBy(p => p.Id)   //just few columns for now
            };

            return View(model);
        }
    }

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NavController is responsible for navigation and showing categories (retrieved from its table) in left column as following:

public class NavController : Controller  {

        private ICategoryRepository repository;
        public NavController(ICategoryRepository repo) {
            repository = repo;
        }

        public PartialViewResult Menu() {
            IEnumerable<string> categories = repository.Categories
                                                .Where(x => x.Visible == "1" /*|| x.Visible == "0"*/)
                                                .Select(x => x.CategoryName)
                                                .Distinct()
                                                .OrderBy(x => x);

            return PartialView(categories);
        }

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Now, I have an HTML page which shows off a left column populated with categories (or let's say report names in the left column) and need to setup and run a query every time user clicks on one of a report/category name.

One thing I know (feel free to correct me if I'm wrong) is that I have to work on CategoryController but using a code as following ends up to getting a type casting error:

public class CategoryController : Controller   {
        private IMetricRepository repository;

        public CategoryController(IMetricRepository metricRepository) {
            repository = metricRepository;
        }

        public ViewResult List(string category)
        {

            MetricsListViewModel viewModel = new MetricsListViewModel {
                Metrics = repository.Metrics
                    .Select(p => p.cs_username)  <<<<<<<<  cannot convert 
            };
        }
    }

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The error is:

Cannot implicitly convert type 'System.Linq.IQueryable' to 'System.Collections.Generic.IEnumerable'. An explicit conversion exists (are you missing a cast?)

This is my first MVC application and I feel like I'm missing something. I could use a constant list of report and use

@Html.ActionLink(GenerateReport1, action ,Controllername)
@Html.ActionLink(GenerateReport2, action ,Controllername)
@Html.ActionLink(GenerateReport3, action,Controllername)
but need to load the report names from a table. Any help is appreciated.

Regards,
Amit

kaufmed

Please provide the definition for the MetricsListViewModel class.