Hello @MarcJo
use this code
DT.AsEnumerable().Sum(Function(r) if(r("A").equals(DBNull.Value) ,0,if(String.IsNullOrEmpty(cstr(r("A"))),0,if(r("A").tostring.contains(","),cdec(r("A").ToString.Replace(",",".")),cdec(r("A")) )))).ToString.Replace(".",",")
Again here The reason for error was blank values…What the above code does is converts the blank values to 0…
Check it and let me know about it