Validate a Time String

[Guest]

Private Function GetValidTime(ByVal atimestring As String) As String

I am writing a function that accepts a string that may contains a time in
format "HH:MM" or it may contain junk data.

How can I check whether the string passed in this function is a valid time.
The function should return a valid time string otherwise it returns "00:00"
in case if invalid timestring was passed.

How can I write that function?


ABB

 

[Siva M]

This is one way to do it:

Private Function GetValidTime(ByVal atimestring As String) As String
Try
DateTime dt = DateTime.ParseExact (atimestring, "HH:mm", null);
Return atimestring
Catch
Return "00:00"
End Try
End Function

Private Function GetValidTime(ByVal atimestring As String) As String

I am writing a function that accepts a string that may contains a time in
format "HH:MM" or it may contain junk data.

How can I check whether the string passed in this function is a valid time.
The function should return a valid time string otherwise it returns "00:00"
in case if invalid timestring was passed.

How can I write that function?


ABB

 

[Ken Tucker [MVP]]

Hi,

I would use a regular expression to validate the time. The
rgular expressions ismatch method will tell you if it is a valid format.

Dim regTime As New
System.Text.RegularExpressions.Regex("^([0-1][0-9]|[2][0-3])[0-5][0-9])$")
Dim t1 As String = "25:12"
Dim t2 As String = "12:45"
Dim t3 As String = "01:12"

Trace.WriteLine(regTime.IsMatch(t1))
Trace.WriteLine(regTime.IsMatch(t2))
Trace.WriteLine(regTime.IsMatch(t3))


Ken
----------------------
Private Function GetValidTime(ByVal atimestring As String) As String

I am writing a function that accepts a string that may contains a time in
format "HH:MM" or it may contain junk data.

How can I check whether the string passed in this function is a valid time.
The function should return a valid time string otherwise it returns "00:00"
in case if invalid timestring was passed.

How can I write that function?


ABB

 

[Herfried K. Wagner [MVP]]

Private Function GetValidTime(ByVal atimestring As String) As String
Try
DateTime dt = DateTime.ParseExact (atimestring, "HH:mm", null);

'null' => 'Nothing'.

 

[Siva M]

Thanks Herfried!

Sorry about it. :-(

Private Function GetValidTime(ByVal atimestring As String) As String
Try
DateTime dt = DateTime.ParseExact (atimestring, "HH:mm", null);

'null' => 'Nothing'.

 

[Guest]

Hi

I tested the solution by replacing 'null' with 'nothing'.

Try passing atimestring as " :" and u will get an exception.

how will this routine work for any invalid string date in atimestring?

ABB

 

[Siva M]

For validating date values, specify the exact date format you are expecting
for ParseExact.

Hi

I tested the solution by replacing 'null' with 'nothing'.

Try passing atimestring as " :" and u will get an exception.

how will this routine work for any invalid string date in atimestring?

ABB