How to Sum Report Items HH:MM:SS in Group footer with reportViewer vb.net 2010

Question

Please Help me,

Column-A    column_B  TimeDiff   <---Datediff() Here i'd used this function

a 2/05/12  00:00:00

a 4/05/12  02:25:17

a 6/05/12  01:45:55

a)Total timeDiff   03:11:12   <--- i need this total Group a  <----Here i got 75:11:12

Column-A    column_B   TimeDiff

B 2/05/12  00:00:00

B 4/05/12  02:25:17

B 6/05/12  01:45:55

B)Total timeDiff   03:11:12

Grand Total 06:22:27

i'd tried This coding 

Time Diff Function
Dim hours As Double=0
Dim mins As Double =0
Dim sec As Double =0
Dim Sum as Double=0
Dim total as integer=0

Public Function formatTimeAdd(ByVal  tempNumberSecond As Integer) 
'Format output

total=total+tempNumberSecond 
Return total
End Function

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

Answer 1

HI Emalai !

Seems like you already have an answer to this in below thread;

http://social.technet.microsoft.com/Forums/en-US/sqlreportingservices/thread/3de19757-c8e4-419a-821e-725ac480048a

From your description, you are designning a client report definition (.rdlc) file. Let's assume the name of the field placed in the Column_A is "Column_A" and the name of the field placed in "Column_B" is "Column_B", and then, I suggest that you refer to the following steps:

1. Drag a Table control to the design surface.
2. Place "Column_B" in the Details row.
3. Add a parent group for the Details group, and set the group to group on the "Column_A" field.
4. Right-click on the details row of the "TimeDiff" column, select "Add Total".
5. Right-click on the textbox that contains "Column_A" field, and select "Add Total"-> "After".

For more information, please refer to the following article:
http://msdn.microsoft.com/en-us/library/ms170712(v=sql.105).aspx

Besides, this question is probably better served by the Visual Studio Report Controls forum where the experts are more familiar with the ReportViewer control. For your convenience, I have included link below:
http://social.msdn.microsoft.com/Forums/en-US/vsreportcontrols/threads?page=1

Thanks, Hasham Niaz