How to Write this Crystal Report formula in SSRS Expression?

I am Having Problem to Convert this Crystal Report formula in SSRS Expression Can Anyone Help me?

Formula 1:

Dim fromExDay as String
Dim toExDay as String
Dim sYr as String
Dim sMonth as String
Dim sDay as String

fromExDay = ToText({wk_TORIO0460_a.HktrExchngDayFrom})
fromExDay = Replace (fromExDay, ",", "" )
fromExDay = Replace (fromExDay, ".", "" )

toExDay = ToText({wk_TORIO0460_a.HktrExchngDayTo})
toExDay = Replace (toExDay, ",", "" )
toExDay = Replace (toExDay, ".", "" )
if Len (Trim(fromExDay)) > 0 and Len (Trim(toExDay)) > 0 then
    sYr = Right(Left(fromExDay, 4),2)
    if sYr <> "99" then
        sYr = LEFT(CStr(CDbl(sYr) + 12),2)
    end if
    sMonth = Mid(fromExDay, 5, 2)
    sDay = Left(Right(fromExDay, 4),2)
    'fromExDay = sYr + sMonth + sDay    
    fromExDay = sYr + sMonth + sDay
    sYr = Right(Left(toExDay, 4),2)
    if sYr <> "99" then
        sYr = LEFT(CStr(CDbl(sYr) + 12),2)
    end if
    sMonth = Mid(toExDay, 5, 2)
    sDay = Left(Right(toExDay, 4),2)
    toExDay = sYr + sMonth + sDay    
    'toExDay = Right(fromExDay, 2)
    Formula = fromExDay + " ～ " + toExDay    
Else
    Formula = ""
End If

Value of ExchangeFrom and ExchangeTO is coming from Database . ExchangeFrom value = 20031031 ExchangeTo value = 200 Is There in Database

Is the return value supposed to be

151010 ~ 1220

There actually weren't many changes needed to convert it to an SSRS VB function. In SSRS, the function doesn't work directly with the field so you need to pass them to the function as parameters. Most of the rest of the VB in your old function should work the same in SSRS - I just removed the ToText functions that aren't in SSRS.

When you call the function from your text box, you pass the fields.

=code.Formula1(Fields!HktrExchngDayFrom.Value, Fields!HktrExchngDayTo.Value)

And here's the function:

Public Function Formula1(ByVal fromExDay as String, ByVal toExDay as String) as String

Dim sYr as String
Dim sMonth as String
Dim sDay as String

fromExDay = Replace (fromExDay, ",", "" )
fromExDay = Replace (fromExDay, ".", "" )

toExDay = Replace (toExDay, ",", "" )
toExDay = Replace (toExDay, ".", "" )

if Len (Trim(fromExDay)) > 0 and Len (Trim(toExDay)) > 0 then
    sYr = Right(Left(fromExDay, 4),2)
    if sYr <> "99" then
        sYr = LEFT(CStr(CDbl(sYr) + 12), 2)
    end if
    sMonth = Mid(fromExDay, 5, 2)
    sDay = Left(Right(fromExDay, 4), 2) 
    fromExDay = sYr + sMonth + sDay
    sYr = Right(Left(toExDay, 4), 2)
    if sYr <> "99" then
        sYr = LEFT(CStr(CDbl(sYr) + 12), 2)
    end if
    sMonth = Mid(toExDay, 5, 2)
    sDay = Left(Right(toExDay, 4), 2)
    toExDay = sYr + sMonth + sDay 
    Formula1 = fromExDay + " ~ " + toExDay    
Else
    Formula1 = ""
End If

End Function 

I think the sDay calculations are incorrect.

sDay = Left(Right(fromExDay, 4),2)      

Seems to be getting the month again. It should probably be

sDay = Right(fromExDay, 2)

or, if it can be a longer string use MID:

sDay = Mid(fromExDay, 7, 2)

Which changes the result to:

151031 ~ 12