Chances are if you have developed a web part in the past, it needed some user input. And if it needed user input then it needs validation.

When you develop webparts you are unable to do use the designer (thanks Microsoft) so you have to be a real coder and declare, instantiate and add the controls entirely programmatically. Including your validation controls. Ok, you've done that. Why doesn't your validation work?

First, you MUST (and I cant stress that enough) instantiate the validators in your overridden OnInit method, not in the CreateChildControls() method. Secondly, set up a validation group so that you can control what the validators are validating (you dont want to validate the whole page) and lastly, you need to ensure that the EnableClientScript property is enabled.

            regexpval.ControlToValidate = this.txtEmail.ID;
            regexpval.ValidationExpression = @"\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*";
            regexpval.ErrorMessage = "Please Enter a valid email address.";
            regexpval.Display = ValidatorDisplay.Dynamic;
            regexpval.EnableClientScript = true;
            regexpval.ValidationGroup = validationGroup;

If you've been diligent then your code will compile, deploy and even let you place it on the page, but for some weird reason it still doesn't work as you think it should. AAAAARGH!

Its a small and very simple fix, the text box you are validating might be instantiated but it doesn't have an ID, D'oh!

All it takes is adding a line like this BEFORE you set up the validators:

txtEmail.ID = "txtEmail";

Happy Validating!

You've developed a brand new site. It's great; there is lots of good content; it's standards compliant; And as it's in .Net you have used the customErrorPages features of the framework. Brilliant. So why does your error page get indexed when you delete files from the site?


The .Net framework detects that your page is no longer there and so sends an HTTP Status Code 302 to the browser along with a redirect to the error page. The error page is then successfully served within the framework and as such sends an HTTP Status Code 200 to the browser. A user may well be able to read the text on the screen that says their file was not found but the bot crawling the site will think the page is still available as it received an HTTP Status Code 200.


To resolve this you need to do two things:

1. Check the page exists - if it doesn't server the error page.
2. Send the correct error code to the browser.

Check the page exists

In your global.asax you need to check the request is a valid one so within the application_BeginRequest code block add the following:

Send the correct error status

Now that you can tell whether your page exists you can send the correct status, in your error page page_load event simply add: