LinQ DataTable Group By - vb.net

Question

I have a datatable in vb.net application. the data table is looking like this:
State Level City
AL T Arlton
AL T Brton
AL T Rurton
CO T Dver
CO T Crodo
WA T Blain
WA T Bwelham
I would like to group the state and do a loop
I tried the following but is not working as expected.
please help
what I tried so far:
Dim result = From r In dt Group r By state = r(0) Into Group Select Group
For Each r In result
Console.WriteLine(r("State"))
Next
The output from the loop should be
AL
CO
WA
Thank you

Answer 1

You cannot call GroupBy on a datatable. So you may first convert the datatable to a collection using the AsEnumerable() method and then apply your group by
Dim itms = dt.AsEnumerable().[Select](Function(x) New With {
Key .City = x.Field(Of String)("City"),
Key .State = x.Field(Of String)("State"),
Key .Level = x.Field(Of String)("Level")
})
Dim uniqueStatesgroupedStates = itms.GroupBy(Function(s) s.State, Function(p) p,
Function(k, v) New With {
Key .State = k,
Key .Item = v
})
' IF you want group records based in State
For Each r In uniqueStatesgroupedStates
Console.WriteLine(r.State)
Next
' IF you want only Unique states from your data table
Dim uniqueStates = itms.[Select](Function(s) s.State).Distinct().ToList()
For Each r In uniqueStates
Console.WriteLine(r)
Next
Your expected output looks like you want only the unique State names, In that case you simply need to do a Select on State property and call Distinct() on that.

Answer 2

I guess you need distinct instead of a group by, If I understood your question correctly following method will work for you.
Dim resultdt As DataTable = dt.DefaultView.ToTable(True, "state")
For Each row In newdt.Rows
Console.WriteLine(row(0).ToString)
Next
DataView.ToTable Method (): Creates and returns a new DataTable based on rows in an existing DataView