How to convert String to Integer in report viewer

Dear Sir,

I need how to convert string to integer values, I have Hours:Minutes: Seconds values are String it's convert to integer seconds , I'd tried below expression but i got #ERROR 

Function GetformatTimeAdd()  as String 

hours=( total ) \ 3600
mins =( total  - hours * 3600) \ 60
sec=( total- hours * 3600-mins*60) 

GetformatTimeAdd=hours.ToString("#,#0.##") & ":" & mins.ToString("#,#00.##") &":" & sec.ToString("#,#00.##") & ""
total=0

End Function

I wrote expression =Code..GetformatTimeAdd()

I got time 

50:26:01

I did convert to Integer(Seconds)

=DateDiff("s","00:00:00",CInt(ReportItems!Texbox11.values))

but i got Error  but i need 181561 seconds values

how to solve the problems 

Please help me

Thanks 

Emalai