Cannot be translated into a LINQ to Entities store expression

I am relatively new to LINQ-to-Entities, but use LINQ-to-SQL a lot. I am using Visual Studio 2013 with Entity Framework 6 and MVC 5. The biggest difference between the two is that Linq2SQL has the ability to perform conversions inside the `SELECT` query itself whereas LINQ2Entities is not as forgiving and must have the right conversion in place before executing the LINQ query. Therefore, I am getting the error: The specified method 'System.Decimal ConvertToDecimal(Byte)' on the type 'BillYeagerDB.EdmxExtensionMethods' cannot be translated into a LINQ to Entities store expression. After doing much research, especially on Stack Overflow with this question, I discovered a link (LINQ to Entities does not recognize the method 'Double Parse(System.String)' method, and this method cannot be translated into a store expression), but he was working with the `ObjectContext` and I am working with the `DbContext`. I'm also sure it will work for me, but I think I'm just designing the extension method incorrectly (which gives me the above error). Note that this specific issue is with the `AvgRating` variable in the LINQ query. Once I can get this to work, I can do the same type of fixing for any other conversions. Note that `AvgRating` is defined as type `Decimal` and `a.Rating.RatingValue` is defined as type `Byte`. If somebody can straighten me out on this, I would greatly appreciate it. Here is my code. I'm trying to use the following query, which I know won't work (as mentioned before) because of the conversion issue. Original LINQ Query: ``` namespace BillYeagerDB { public class BillYeagerDB { public async Task<List<RestaurantList>> GetRestaurantListAsync() { try { using (BillYeagerEntities DbContext = new BillYeagerEntities()) { DbContext.Database.Connection.Open(); var restaurants = await DbContext.Restaurants.GroupBy(g => g).Select(s => new RestaurantList() { Name = s.Key.Name, City = s.Key.City, Phone = s.Key.Phone, AvgRating = s.Average(a => Convert.ToDecimal(a.Rating.RatingValue)), NbrOfPeopleRating = s.Distinct().Count(c => Convert.ToBoolean(c.RatingId)), Id = s.Key.Id }).ToListAsync(); return restaurants; } } catch (Exception) { throw; } } } } ``` Update I needed to do to my EDMX file ``` <edmx:ConceptualModels> <Schema Namespace="BillYeagerModel" Alias="Self" annotation:UseStrongSpatialTypes="false" xmlns:annotation="http://schemas.microsoft.com/ado/2009/02/edm/annotation" xmlns="http://schemas.microsoft.com/ado/2009/11/edm"> <Function Name="ParseDecimal" ReturnType="Edm.Decimal"> <Parameter Name="bytevalue" Type="Edm.Byte" /> <DefiningExpression> cast(bytevalue as Edm.Decimal) </DefiningExpression> </Function> ``` C# extension method which is a class on the root of my project - not inside my EDMX ``` namespace BillYeagerDB { public partial class EdmxExtensionMethods : DbContext { [DbFunctionAttribute("BillYeagerDB", "ParseDecimal")] public static Decimal ParseDecimal(byte bytevalue) { return Convert.ToDecimal(bytevalue); } } } ``` Updated Linq query - note no design time compile errors and project compiles successfully ``` namespace BillYeagerDB { public class BillYeagerDB { public async Task<List<RestaurantList>> GetRestaurantListAsync() { try { using (BillYeagerEntities DbContext = new BillYeagerEntities()) { DbContext.Database.Connection.Open(); var restaurants = await DbContext.Restaurants.GroupBy(g => g).Select(s => new RestaurantList() { Name = s.Key.Name, City = s.Key.City, Phone = s.Key.Phone, AvgRating = s.Average(a => EdmxExtensionMethods.ConvertToDecimal(a.Rating.RatingValue)), NbrOfPeopleRating = s.Distinct().Count(c => Convert.ToBoolean(c.RatingId)), Id = s.Key.Id }).ToListAsync(); return restaurants; } } catch (Exception) { throw; } } } } ```