Problem creating a LINQ query, filtering old duplicates, VB

Question

Hello,

I've got a problem and It seems I'm not able to solve it...

I have a table with circa these fields (simplified)

autoID, TruckPlate, Departure Location, Arrival Location, departure date, arrival date

this table is filled of recurring TruckPlates that go from  a location to another, and again and again. so I have many similar truckplates in the table, because the truck number of the company is limited of course

What I need is a situation of what trucks are at the moment of the query in a given "arrival location",

so i need first to distinct all the plates ordered by arrival date descending, to remove duplicate.
so I have a list of most recent unique plate in the table

and then keep just the ones have arrival in (for example) London.
and select all fields of these records in my datagridview table


I created a combined query, with a first query that distincts the truck plates by date and the second one that make a for each of the 1° query and select the ones with the given location

but I'm not able to put it in the table all together!

is like this, (more or less..)

dim queryuniqueplate = from truck in db.travels ....

order by date desc

select truck.plate distinct

for each plate in queryuniqueplate

dim queryLondon = from t in db.travels

where arrival like "london"

select t

me.truckingbindingsource.datasource = queryLondon
msgbox("next")  ->>>>> (to remove, just something that shows the query works)
next

when i press next i can see all the results but i want to see them all together in the table! not load them one at a time, how can i do it?

I hope I was clear, is not very easy to explain

Answer 1

Hi Valnuke,

Perhaps you can try the following code snippet to combine the two queries above.

Code Snippet

dim queryuniqueplate = from truck in db.travels

order by date desc

select truck.plate distinct, truck.autoID, truck.arrival, truck.deparure, truck.date

 

For Each c In queryuniqueplate

    Debug.WriteLine(c)

Next

 

 

For more information about LINQ in VB.Net, please check the URL below.

http://msdn2.microsoft.com/en-us/library/bb763068.aspx

Regards,

Xun