Cannot implicitly convert type System.Collections.Generic.IEnumerable<> to bool

Question

I\'m developing an ASP.NET MVC 4 Application and I\'m trying to run this Lambda expression in Entity Framework 5.

var customer = db.GNL_Customer.Where(d =>         


        

Answer 1

Use Where ( Any ) in last statement to select customers which have at least one product satisfying your conditions:

var customer = db.GNL_Customer
   .Where(d => d.GNL_City.FKProvinceID == advancedProvinceID || advancedProvinceID == null)
   .Where(d => d.FKCityID == advancedCityID || advancedCityID == null)
   .Where(d => d.FKDepartmentStoreID == advancedDepartmentStoreID || advancedDepartmentStoreID == null)
   .Where(d => brandID == null || d.GNL_CustomerLaptopProduct.Any(r => r.BrandName == brandID));

Answer 2

You might want another .Any instead of a .Where in your .Any clause at the end:

var customer = db.GNL_Customer.Where(d => d.GNL_City.FKProvinceID == advancedProvinceID || advancedProvinceID == null)
            .Where(d => d.FKCityID == advancedCityID || advancedCityID == null)
            .Where(d => d.FKDepartmentStoreID == advancedDepartmentStoreID || advancedDepartmentStoreID == null)
            .Any(d => d.GNL_CustomerLaptopProduct.Any(r => String.Compare(r.BrandName, brandID) == 0 || brandID == null));