Then I could use the extension like this:
if (mySeries.In(Enum.Series.ProMazda, Enum.Series.Usf2000)) myChassis = "Tatuus";
As for the other two methods, well… When is a null not a null? When it’s a System.DBNull.Value, of course! SQL Server pros who have spent any time in the .NET Framework will recognize this awkwardness:
var p = new System.Data.SqlClient.SqlParameter("@myParam", System.Data.SqlDbType.Int);
p.Value = (object)myVar ?? System.DBNull.Value;
With the extension, the second line becomes:
p.Value = mVar.ToDbNull();
I like it that Jay ended up going with a different language than T-SQL. It’s no F#, but it’ll do.