Filter Datatable Error

[d_liberati]

Hi,
i have this assign expression:
dt1=(From d In dt
Group d By k=d(“colum1”).toString.Trim Into grp=Group
Where grp.Count =1
Select grp.First()).CopyToDatatable

this return an error “The source contains no DataRows”.
How can i catch / prevent this error?

Thanks

[ppr (Peter Preuss)]

@d_liberati
you can apply this pattern for handling empty filter result:

drDuplicates from this example is of datatype List(Of Datarow)!

[d_liberati]

Thanks, but it doesn’t work

[ppr (Peter Preuss)]

@d_liberati
please tell us what is not working so we can help. Thanks

[d_liberati]

@d_liberati

dt1

it is possible to check only if dt1 is empty?

[ppr (Peter Preuss)]

@d_liberati
so the problem is not the pattern it is the flow implementation

checking dt1 is Null
isNothing(dt1)

• is not the case so youl would receive a not set to instance exception

checking empty datatable
dt.Rows.Count=0

• (will not harm the pattern as long there is a columk in the column definition)

otherwise go for debuging, set a breakpoint before the assign statement and inspect dt1 within the locals

Also ensure that variables are correct wired for the different returns

add AsEnumerable to dt
From d In dt.AsEnumerable
Group …