Issue in data filtering

[ppr (Peter Preuss)]

Give a try on:
Assign activity
leftside: dtFiltered | DataType:DataTable
Right side:

(From d in YuurDataTableVar.AsEnumerable
let acmn = d(yourColNameOrIndex).toString.Trim
Where acmn.length = 8 Or acmn.length = 10
Select r=d).CopyToDataTable

handling empty filter result can be done with following patterns: