Question

I have inherited some code (that happens a lot!) which looks a bit like this: (namespace omitted)

public partial class SpatialDatabase : global::System.Data.Objects.ObjectContext
{
    public string MY_PROCEDURE(Decimal arg1, Decimal arg2)
    {
        using (EntityConnection conn = new EntityConnection(this.Connection.ConnectionString))
        {
            conn.Open();

            object a = new System.Data.Objects.ObjectContext(new EntityConnection());

            EntityCommand cmd = conn.CreateCommand();
            cmd.CommandText = "SpatialDatabaseContext.MY_PROCEDURE";
            cmd.CommandType = CommandType.StoredProcedure;

            cmd.Parameters.AddWithValue("ARG1", arg1);
            cmd.Parameters.AddWithValue("ARG2", arg2);

            EntityParameter resultParam = cmd.Parameters.Add("RESULT", DbType.String, 100);
            resultParam.Direction = ParameterDirection.Output;

            int c = cmd.ExecuteNonQuery();

            return (string)resultParam.Value;
        }
    }
}

This gives me a sqiggly blue line under my class name with the error message.

I know that this code works. This is running elsewhere on site just fine.
So why would this copy give me this error?

[Edit]

In reality, what happens is that the missing constructor is added when the EDMX file is built from the database objects. That’s why it’s a partial class!
We learn something new every day!

[/Edit]

Answer 1

Since ObjectContext doesn’t have any constructor that takes 0 arguments and you haven’t called any base(…) constructor with your SpatialDatabase class, your code is implicitly calling default constructor base() for the base class.

Your current code is equivalent to:

public partial class SpatialDatabase : global::System.Data.Objects.ObjectContext
{

       SpatialDatabase() : base() //Problem is here
       {
       }

}

You need to call one of the following base constructor with your class constructor

• ObjectContext(EntityConnection)
• ObjectContext(String)
• ObjectContext(EntityConnection, String)
• ObjectContext(String, String)