In a thread here: http://www.llblgen.com/tinyforum/Messages.aspx?ThreadID=3503&HighLight=1

Otis mentions operator overloading being made simpler in the new version of LLBLGen (This was back in 2005)

What's the best way to do this in LLBLGen Pro 2.0:

            // Fields
            ResultsetFields fields = new ResultsetFields(2);
            fields.DefineField(VehiclesFieldIndex.VehicleId, 0, "VehicleId");
            fields.DefineField(VehiclesFieldIndex.Model, 1, "VehicleFullname");

            Expression modelExp = new Expression(" ", ExOp.Add, EntityFieldFactory.Create(VehiclesFieldIndex.Model));
            Expression fullExp = new Expression(EntityFieldFactory.Create(ManufacturersFieldIndex.Name), ExOp.Add, modelExp);
            fields[1].ExpressionToApply = fullExp;

(Code taken from the linked article. I'm using VB.NET 2005 with self servicing but I'm sure the code will be about the same for either language.

Here is a shorter form:

            Expression someExp = new Expression(" ", ExOp.Add, VehicleFields.Model);
            Expression fullExp = new Expression(ManufacturersFields.Name, ExOp.Add, someExp);
            fields[1].ExpressionToApply = fullExp;

You may also try the following short version:

            fields[1].ExpressionToApply = new Expression(ManufacturersFields.Name + new Expression(" " + VehicleFields.Model));