using linq to populate ddl query issue relating to duplicate
records

Hi 
I would like to retreive a category list from my product list but there are many
products with the same category name and i get multiple entries of the same
category in my ddl.  How do i change my query to avoid duplicates ?

Thanks in advance 

Dim prod = From u In db4.products _
                   Where u.category = ddlproduct.SelectedItem.Text _
                    Select u.prodid, u.description

I don't use LINQ much in VB.Net, but you just need to call Distinct something
like this: 

Dim prod = (From u In db4.products _
           Where u.category = ddlproduct.SelectedItem.Text _
           Select u.prodid, u.description).Distinct()

thanks so much.  ;)

Using "distinct" without knowing WHY you have duplicate records coming
back from your query is a BAD idea.

You may not be solving the problem, you may just be hiding it for later, when it
will be an even bigger pain to fix.

 Adding a distinct without knowing why is the logical equivalent of this:

 

try 
 {
    doSomething();
 }
 catch
 {
}

Yep, the above error does not go away, but it is still happening, and that could
be very bad. 


 

So, WHY are you getting duplicate records?  Are you querying from a table or a
view?  If a view, the view will need to be fixed if it is not supposed to return
duplicate records.

If a table, exactly what is being duplicated?  prodid?  description?  If so,
shouldn't you have primary or unique key constraints using those columns in the
database?

shaunie2.0:

 Hi David, thanks for the response.  I do know why i was getting duplicate
records back,  i just needed to filter the duplicated out.  Since the categories
column in the products table may have many products from the same category i
just needed to retreive all the different categories from that table.




I guess there isn't a "categories" table that you could query for that
purpose.