How to validate Date entries.

30 Jul 2006 12:29 PM

YardDancer

Hi All,

Does anybody have a routine for validating a date or DateTime entry in a
textbox.

I know i can use one of the DateTime.Parse(textbox.text) methods which
would throw a Fromat Exception.

What i am after is something like a IsNumeric() fuction or way i can test a
value if it is dateTime value and recieve a boolean answer i.e. true or
false.

Yard Dancer
Practicing at home before I attempt to dance at the hall.

30 Jul 2006 1:00 PM

Ken Tucker [MVP]

Hi,

            If you are using vb 2005 I would use DateTime.TryParse otherwise
I would use a regex.

http://msdn2.microsoft.com/en-us/library/system.datetime.tryparse.aspx

        Dim dtnow As DateTime

        If DateTime.TryParse("1/1/2006", dtnow) Then
            Me.Text = dtnow.ToString
        End If

Regex example

        Dim dtNow As DateTime
        Dim strDate As String = "1/1/2006"
        Dim regDate As New
System.Text.RegularExpressions.Regex("^\d{1,2}\/\d{1,2}\/\d{4}$")
        If regDate.IsMatch(strDate) Then
            dtNow = Date.Parse(strDate)
            Me.Text = dtNow.ToString
        End If

http://www.regexlib.com/Search.aspx?k=date

Ken
---------------------
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"YardDancer" <dancer_y***@hotmail.com> wrote in message
news:OiLzXP9sGHA.1876@TK2MSFTNGP06.phx.gbl...
> Hi All,
>
> Does anybody have a routine for validating a date or DateTime entry in a
> textbox.
>
> I know i can use one of the DateTime.Parse(textbox.text) methods which
> would throw a Fromat Exception.
>
> What i am after is something like a IsNumeric() fuction or way i can test
> a value if it is dateTime value and recieve a boolean answer i.e. true or
> false.
>
> Yard Dancer
> Practicing at home before I attempt to dance at the hall.
>

30 Jul 2006 1:36 PM

YardDancer

I am Programming with VB.NET 2003

--
Yard Dancer
Practicing at home before I attempt to dance at the hall.

Show quoteHide quote

"Ken Tucker [MVP]" <vb***@bellsouth.net> wrote in message
news:ux3w9g9sGHA.4612@TK2MSFTNGP06.phx.gbl...
> Hi,
>
>            If you are using vb 2005 I would use DateTime.TryParse
> otherwise I would use a regex.
>
> http://msdn2.microsoft.com/en-us/library/system.datetime.tryparse.aspx
>
>        Dim dtnow As DateTime
>
>        If DateTime.TryParse("1/1/2006", dtnow) Then
>            Me.Text = dtnow.ToString
>        End If
>
> Regex example
>
>        Dim dtNow As DateTime
>        Dim strDate As String = "1/1/2006"
>        Dim regDate As New
> System.Text.RegularExpressions.Regex("^\d{1,2}\/\d{1,2}\/\d{4}$")
>        If regDate.IsMatch(strDate) Then
>            dtNow = Date.Parse(strDate)
>            Me.Text = dtNow.ToString
>        End If
>
> http://www.regexlib.com/Search.aspx?k=date
>
> Ken
> ---------------------
> "YardDancer" <dancer_y***@hotmail.com> wrote in message
> news:OiLzXP9sGHA.1876@TK2MSFTNGP06.phx.gbl...
>> Hi All,
>>
>> Does anybody have a routine for validating a date or DateTime entry in a
>> textbox.
>>
>> I know i can use one of the DateTime.Parse(textbox.text) methods which
>> would throw a Fromat Exception.
>>
>> What i am after is something like a IsNumeric() fuction or way i can
>> test a value if it is dateTime value and recieve a boolean answer i.e.
>> true or false.
>>
>> Yard Dancer
>> Practicing at home before I attempt to dance at the hall.
>>
>
>

30 Jul 2006 3:21 PM

Kerry Moorman

YardDancer,

What about VB's IsDate function?

Kerry Moorman

Show quoteHide quote

"YardDancer" wrote:

> Hi All,
>
> Does anybody have a routine for validating a date or DateTime entry in a
> textbox.
>
> I know i can use one of the DateTime.Parse(textbox.text) methods which
> would throw a Fromat Exception.
>
> What i am after is something like a IsNumeric() fuction or way i can test a
> value if it is dateTime value and recieve a boolean answer i.e. true or
> false.
>
> Yard Dancer
> Practicing at home before I attempt to dance at the hall.
>
>
>

30 Jul 2006 8:13 PM

YardDancer

Hi Kerry,

I want to write all my routines using methods and properties that are
consistent
with the .Net Framework class library. I am trying to avoid using
functions
from the VB run-time library.

--
Yard Dancer
Practicing at home before I attempt to dance at the hall.

Kerry Moorman" <KerryMoor***@discussions.microsoft.com> wrote in message

Show quoteHide quote

news:BFFACFA5-4EBF-49FA-8135-5599A1AE817C@microsoft.com...
> YardDancer,
>
> What about VB's IsDate function?
>
> Kerry Moorman
>
> "YardDancer" wrote:
>
>> Hi All,
>>
>> Does anybody have a routine for validating a date or DateTime entry in a
>> textbox.
>>
>> I know i can use one of the DateTime.Parse(textbox.text) methods which
>> would throw a Fromat Exception.
>>
>> What i am after is something like a IsNumeric() fuction or way i can
>> test a
>> value if it is dateTime value and recieve a boolean answer i.e. true or
>> false.
>>
>> Yard Dancer
>> Practicing at home before I attempt to dance at the hall.
>>
>>
>>

30 Jul 2006 7:00 PM

Rad Dec [C# MVP]

It's tricky to write such a validation routine because "invalid date" is
quite relative.

For instance "13/1/2006" is a valid in some regions but not in others.

If you know the region you can do this:

string UK="13/1/2006";
DateTime UKDate = DateTime.Parse(UK,new System.Globalization.CultureInfo("en-gb"));

You could probably put this in a function and catch any format exceptions
and return false.

Show quoteHide quote

> Hi All,
>
> Does anybody have a routine for validating a date or DateTime entry
> in a textbox.
>
> I know i can use one of the DateTime.Parse(textbox.text) methods
> which would throw a Fromat Exception.
>
> What i am after is something like a IsNumeric() fuction or way i can
> test a value if it is dateTime value and recieve a boolean answer i.e.
> true or false.
>
> Yard Dancer
> Practicing at home before I attempt to dance at the hall.