how to compare current date to a future date and validate it in ASP.NET

[James P.]

Hello there,

In my asp.net page using VB, I have a date text field in mm/dd/yyyy
format. When a date is entered, I'd like to validate it to make sure
the date is greater than or equal to the current date. If not, I'd
like to display the error message to ValidationSummary.

It seems to make sense to me to use CompareValidator but the problem
is put the current date into CompareValidator. So, I created a hidden
text field in my aspx. In my VB code behind, I load current date to
that text field. Then, I created a CompareValidator to compare this
current date to the text field containing date entered by the user.
In my Page_Load, I have Page.Validate to activate the validation.
When I run it, the first round through, the validationSummary worked
and displayed the warning message I wanted (that date entered can't be
less than current date). However, it did not work after that. I
think the problem is server validation did not work properly.

My alternative way is to use client validation using CustomValidator.
Pass in two date fields: current date and entered date and compare.
Unfortunately, I don't know well neither javaScrip nor any other
script languages to do it. The problem I am having with this approach
is getting current date in the mm/dd/yyyy format so I can compare to
what the user enters in that format. Date() function is javascrip
returns a different format. And I think Now() returns both date and
time.

Any suggestions are greatly appreciated. Thank you in advance,
James

 

[Teemu Keiski]

Hi,

yes you'd use CompareValidator, but you need to give it the value as
correctly formatted to the ValueToCompare property.

First you'd put the validators something like this (I've omitted buttons and
ValidationSummary to keep it concise):

***
<asp:TextBox id="TextBox1" runat="server"></asp:TextBox>

<asp:CompareValidator id="compDateDataTypeValidator"
ControlToValidate="TextBox1" Operator="DataTypeCheck"
Type="Date" runat="server" ErrorMessage="You must enter a valid
date"></asp:CompareValidator>

<asp:CompareValidator id="compDateValidator"
ControlToValidate="TextBox1" Operator="LessThan" Type="Date"
runat="server" ErrorMessage="Entered date must be less than current
date"></asp:CompareValidator>
***

Then additionally you'd set in code the ValueToCompare property for the
CompareValidator (compDateValidator) which compares the dates. Like this:

***
compDateValidator.ValueToCompare = DateTime.Now.ToString("MM/dd/yyyy")
***
As you can see, it is given as string and the easiest way is to get it from
DateTime.Now and then format using string formatting so that it passes for
CompareValidator (standard date format based on current locale and culture)

--
Teemu Keiski
MCP, Microsoft MVP (ASP.NET), AspInsiders member
ASP.NET Forum Moderator, AspAlliance Columnist
http://blogs.aspadvice.com/joteke

 

[Teemu Keiski]

Sorry, I re-read your post and you said date format dd.mm.yyyy. TThen just
change the format string to "dd/MM/yyyy" (or dd.MM.yyyy). /'s are considered
culture-speficic separators to dates and will be replaced with dots.

--
Teemu Keiski
MCP, Microsoft MVP (ASP.NET), AspInsiders member
ASP.NET Forum Moderator, AspAlliance Columnist
http://blogs.aspadvice.com/joteke

 

[James P.]

Sorry, I re-read your post and you said date format dd.mm.yyyy. TThen just
change the format string to "dd/MM/yyyy" (or dd.MM.yyyy). /'s are considered
culture-speficic separators to dates and will be replaced with dots.

--
Teemu Keiski
MCP, Microsoft MVP (ASP.NET), AspInsiders member
ASP.NET Forum Moderator, AspAlliance Columnist
http://blogs.aspadvice.com/joteke

Teemu,

Thanks a lot for responding and trying to help me. Yes, you got it
right the first time with "mm/dd/yyyy" as I would like. I used your
suggestion and I got "The value 'DateTime.Now.ToString("mm/dd/yyyy")'
of the ValueToCompare property of 'cvDate' cannot be converted to type
'Date'". Any other suggestions are appreciated.

James

 

[Teemu Keiski]

If you see my VB code, it goes through compilation. You have a syntax typo
there. What's *exactly* the code you use for this line?

--
Teemu Keiski
MCP, Microsoft MVP (ASP.NET), AspInsiders member
ASP.NET Forum Moderator, AspAlliance Columnist
http://blogs.aspadvice.com/joteke

 

[phamtasmic]

Teemu,

Here is what I used:
<asp:CompareValidator id="cvCompareDate" style="Z-INDEX: 115; LEFT:
456px; POSITION: absolute; TOP: 180px"
runat="server" ControlToValidate="txtFutureEventDate"
ErrorMessage="toot toot" Operator="GreaterThanEqual"
Type="Date"
ValueToCompare='DateTime.Now.ToString("MM/dd/yyyy")'></asp:CompareValida
tor>

I even tried ("M/d/yyyy"). I got the same error message like I describe
earlier.

James

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[Teemu Keiski]

You can't assign the value on inline code that way. I used it in
code-behind, but anyway, it should be in code (in your case put code in
Page_Load, for example) to use it the way I demonstrated

*** With the code ***
cvCompareDate.ValueToCompare = DateTime.Now.ToString("MM/dd/yyyy")
******************

Another way with inline way would be with binding. e.g set the attribute
like this:

***With inline ***
ValueToCompare='<%#DateTime.Now.ToString("MM/dd/yyyy")%>'
***************

Additionally you would need to call DataBind for the CompareValidator
control in question (or if suits, for the whole Page at the same time with
Page.DataBind() ) to get this way to work

 

[phamtasmic]

Teemu,

You are right about that. I put that code in the Init event for the
textbox to get the current date and it worked.

Thanks a lot for helping,
James