Question

On my reporting application which is developed using SSRS 2005, I have a parameter of type string which accepts time. the time should be in the format “HH:mm:ss” How can I check if the input string is of correct format?

I tried to do the following
IsDate(TimeValue(parametr!stime.Value))
This returns true as long as the value is within range. But if the value is 24:00:00 or a wrong value then an exception is thrown.

I also tried to create a function in the report code as follows:

Public Function CheckNum(sNum as String) as Boolean
Dim msg as String
msg = ""
Try
If IsDate(TimeValue(sNum))=1 Then
Return True
Else
msg="Parameter must be a number"
End If
Catch ex as Exception
Return False
End Try
If msg <> "" Then 
MsgBox(msg, 16, "Parameter Validation Error")
Err.Raise(6,Report) 'Raise an overflow
End If
End Function

And when I input a value 24:00:00 I still get an error

” The conversion of a char type to datetime data type resulted in an out of range date time value”
How can I handle the exception so that I don’t the error?

EDIT:

public Function CheckNum(sNum as String) as Boolean

Dim REGEX_TIME = "^(([0-1]?[0-9])|([2][0-3])):([0-5]?[0-9])(:([0-5]?[0-9]))?$"       
If System.Text.RegularExpressions.Regex.IsMatch(sNum, REGEX_TIME) Then
Return True
Else
Return False
End If
End Function

Then I assigned a parameter(validateTime) value as =Code.CheckNum(Parameters!sTime.Value)

But the value of the parameter is always true. When I specify a value greater than 23, I still see the error. Please see the image

Answer 1

Instead of using IsDate function, use VB.NET regular expressions. SSRS allows full use of .NET functions.
See an example of time regex.
A good tutorial on regex.

Example Code Console Application

Imports System.Text.RegularExpressions

Module Module1

    Sub Main()

        Dim REGEX_TIME = "^(([0-1]?[0-9])|([2][0-3])):([0-5]?[0-9])(:([0-5]?[0-9]))?$"
        Dim InputList As List(Of String) = New List(Of String)
        InputList.Add("25:00:21")
        InputList.Add("22:00:21")
        InputList.Add("AA:00:21")
        InputList.Add("17:21:02")
        For Each input As String In InputList
            If Regex.IsMatch(input, REGEX_TIME) Then
                Console.WriteLine("TIME " + input + " IS OK")
            Else
                Console.WriteLine("TIME " + input + " IS NOT OK")
            End If
        Next
    End Sub
End Module

Output is :

TIME 25:00:21 IS NOT OK
TIME 22:00:21 IS OK
TIME AA:00:21 IS NOT OK
TIME 17:21:02 IS OK