I would like to use Linq instead of below function :

Friend Function IsCollectionInTable2(ByVal apps As DataTable, ByVal collectionId As String) As Boolean
    For Each row As DataRow In apps.Rows
        If row("CollectionId").ToString = collectionId Then Return True
    Next
    Return False
End Function

The best I can do is below:

Friend Function IsCollectionInTable(ByVal apps As DataTable, ByVal collectionId As String) As Boolean
    Return (From row In apps.AsEnumerable()
             Where (row.Field(Of String)("CollectionId") = collectionId)
             Select row.Field(Of String)("CollectionId")).Count > 0
End Function

I would like to use Exists or Any in above function. Performance could be an issue,