dotnet windows forms databinding: Hi,

I am creating a little invoicing application in C# on an access database.
Main DB-structure: customers -> * invoice -> * invoicelines
I created a typed dataset for it, (with xsd), including all constraints.

I have an "invoice" screen, with:
First section: Some customer fields, (read-only, because i arrive in the
screen with customer allready selected).
Second section: Some invoice fields.
Third section: A invoice-lines datagrid.

I would like to have the invoice-key as an only parameter for this screen.

I created an instance of my dataset on this screen.

I have a data-adapter for the customers table, of which I changed the select
command to accept a parameter (customer key).
I have a data-adapter for the invoices table, of which I changed the select
command to accept a parameter (invoice key).
I have a data-adapter for the invoicelines table, of which I changed the
select command to accept a parameter (invoice key).

Problem 1: When I use the invoice-data-adapter to fill my
dataset.invoicetable, i get a constraint error (because the customer is not
yet loaded in the dataset).
Temporary solution: I have an extra parameter for my invoice screen that
represents the customer key. (of which i would like to get rid of, because
it is contained in the invoice),
So I first load the customer, afterwards I load the invoice in the dataset.
No constrain errors any more.
Can anybody tell me how I can solve this in a better way, not by an extra
parameter for the screen? (and not by not using constraints in my typed
dataset)

Problem 2: I use the invoice-lines-data-adapter to fill my
dataset.invoicelinestable.
This works fine, but when I insert a new line, the primary key used for that
line, is not filled in with my access autonumber, but with one value higher
than the highest key of the selected invoicelines.
I have fixed it temporarly by filling my dataset.invoicelinestable without
the invoice parameter, so all lines are loaded into my dataset, and then of
course the highest number is correct. But I had to disable my constraints
for this, because not all invoices (parents of the invoicelines) are loaded
in my dataset. When I bound my datagrid to the foreign key between invoices
and invoicelines, my datagrid contained only the appropriate invoicelines
for that invoice. This solution doesn't seem to be very clean to me, because
i don't like the idea of loading ALL my invoicelines into my dataset.
Again, can this be solved in a better way, or is this the "only good" way to
do it...?

Thanks in advance,
Steven.

Hi,

[quoted text, click to view]

You could also do something like:
- disable constraints
- load invoice, get customer_id from that
- load customer
- load invoice-lines
- enable constraints (will also check data already loaded)

Or you could do a query using Command.ExecuteScalar to get the customer_id
from the invoice_id.

[quoted text, click to view]

For auto-generated key fields the key value of inserted rows is really
temporal, it's still the DB (or jet) that generates the actual key that will
be used and you can retrieve it during a DataAdapter.Update(...).

See
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnadonet/html/manidcrisis.asp
scroll to Microsoft Access/JET Issues, see RowUpdated eventhandler

HTH,
Greetings


[quoted text, click to view]

Regarding Problem 1, change the order of the TableAdapter.Fill calls to
reflect the referential integrity chain of your tables.

Good luck...