当变量实际上在正确的范围内时出现错误 CS0103

Question

I have this control (db is the Entity Framework context):

if (db.Sites.Any(s => s.Name.Equals(name))) throw new NameAlreadyInUseException(name);

When I run my tests and debug it fails giving me the error:

Error CS0103: the name 's' does not exist in the current context.

I honestly can't get my head around it and Google hasn't really been helping... any help is appreciated, thanks in advance. Isn't s used correctly here? (I'm still learning, so maybe I missed something but my code here looks ok to me)

Edit: the debugger triggers the error on this line and I am not using s in any other place other than inside that if statement. (I edited the line to show what happens with the if)

Edit2: complete code of the function

public void CreateSiteOnDb(string connectionString, string name, int timezone, int sessionExpirationTimeInSeconds,
            double minimumBidIncrement)
        {
            CheckInput_CreateSiteOnDb(connectionString, name, timezone, sessionExpirationTimeInSeconds, minimumBidIncrement);

            try
            {
                using (var db = new AuctionSiteContext(connectionString))
                {
                    if (db.Sites.Any(s => s.Name.Equals(name))) throw new NameAlreadyInUseException(name);

                    var site = new Entities.Site
                    {
                        Name = name,
                        Timezone = timezone,
                        MinimumIncrement = minimumBidIncrement,
                        SessionExpirationInSeconds = sessionExpirationTimeInSeconds
                    };

                    db.Sites.Add(site);
                    db.SaveChanges();
                }
            }
            catch(NameAlreadyInUseException)
            {
                throw;
            }
            catch(Exception)
            {
                throw new UnavailableDbException();
            }
        }

Edit3: Error as shown during debugging

Answer 1

It is not in the right scope.

In the screenshot you are in the scope of CreateSiteOnDb -> try -> using , but s does not belong to that context.

In very basic terms s => .... is converted to function of a class, and it is called from inside Any . so let's assume that our expression is function named Steve . Steve would look like this:

bool Steve(ISite s)
{
  return s.Name.Equals(name);
}

this means s is the parameter of Steve , and is only valid inside Steve , which becomes CreateSiteOnDb -> try -> using -> Any -> Steve

So to see s you need to be in two more levels. Please, put your cursor inside the expression and then put a breakpoint.