Property value "get" returns 0 even though there's a value

This happens on the WASM in a blazor project. When in debug and hovering on c.Id you can see there is a value, but when you assign it to a variable it assigns the value 0. This causes the ToDictionary function to fail because of duplicate keys (0) while there is no Id with a value of 0 in the collection.

When I am in debug mode and I hover over c.Id, it shows the id, when I assign it to a variable and I hover over that variable it shows 0. How is that even possible?

Here’s the simplified version of the code that fails private void CollectionToDictionary<T>(List<T> collection) where T : IUniqueResource { var dictionary = collection.ToDictionary(t => t.Id, t => t); return dictionary; }

Here’s the simplified code of the class implementing : IUniqueResource ` public interface IUniqueResource { public long Id { get; } }

public class BaseDealerLocation :  IUniqueResource
{
        public long Id { get; set; }
}

public class DealerLocation : BaseDealerLocation
{}

public class GameTable : DealerLocation
{}

`

Here’s a simplified sample of what the data being passed to the method looks like: var gameTables = new List<GameTable> { new GameTable { Id = 1 }, new GameTable { Id = 2 }, new GameTable { Id = 3 }, new GameTable { Id = 4 }, new GameTable { Id = 5 }, };

[javiercn]

How do you explain when you are in debug mode and you evaluate the Id in the immediate window or by hovering you get the proper value, but when you try to assign it to a variable it assigns 0?

That might be a bug in the debugger/inmediate window where it’s showing the field on the base class instead of the value the runtime produces (that’s why the differences happen, but TBH this is a C# question, so don’t take me as an authoritative source 😃)

That said I did get a warning, but I’d expect to get an error if it’s going to be causing bugs such as that.

This has been historically the C# behavior. WarningsAsErrors is always an option here. In general it’s discouraged to hide members unless you truly know what you are doing.

What was being passed to the method was the derived class so in that case I would expect to get the value from the derived class since it “replaces” the base class version. At least that’s what normally happens with polymorphism.

That’s not how hiding works. Your property is not virtual, and the binding to get_Id() is done at compile time based on the compile time type. Your generic method is calling IUniqueResource.Id which is implemented by BaseType

[mkArtakMSFT]

Thanks @danypellerin. We’ll wait for you to share a small repro project so that we can move forward with this.