My personal preference when heavily using e.g. 'StringBuilder' or other 'fluent' interfaces that 'return this' is to define a helper method, a la

let sb = new StringBuilder()

let Append (s:string) = sb.Append(s) |> ignore

...

Append("foo")

Append("bar")

(Alternatively, one could define extension methods like sb.AppendIgnore("foo") maybe.)

When just using such APIs lightly or in passing, I bite the bullet and sprnkle a handful of "|>ignore"s into the code.

1) Why don't you use a SQL join instead of a lot of queries for different values of make?

2) Abandon imperative datastructures (.NET List) and embraaaace Functional ones (F#'s list).

3) Supposing you use a join, and you get a datatable with all the models and makes you can collect all models with

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    let dt = someDataTable
    let models = dt.Rows |> Seq.cast<System.Data.DataRow> |> Seq.map (fun dr -> (dr.["Model"].ToString()))

or even better, into a dictionary Make -> list of models:

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    let dt = someDataTable
    let models = dt.Rows
                    |> Seq.cast<System.Data.DataRow>
                    |> Seq.map (fun dr -> (dr.["Make"].ToString(), dr.["Model"].ToString()))
                    |> Seq.groupBy fst (* Make *)
                    |> Map.ofSeq

My first F# groupBy [B]

thanks for the info Mau. My goal is to take each make and make a list of all the models in each make and sort the list of each model (assign a sort seq) to each (make model) pair, but the list has to be sorted by model of each make.

Also the sorted Model is not "string" sorted, in c# I use an Icomparer to accomplish my specialized sorting.

Numbers come after letters, spaces are sorted first so:

F Series would come before

Fiesta

All the Makes are sorted (regular).

The goal is to update pub_makemodellst with a "model sortseq"

Given that having 2 lists of makes and models where I can iterate through makes to get each model list

sort the model list

and run an update query to populate a sort sequence for each model so that when I run this query:

select make, model, sortseq from pub_makemodellst order by make, sortseq

The records come back sorted.