RequiredFieldValidator in connected web parts

I plan on posting a tutorial on how to easily create connected web parts, but I wanted to write a short post on a unique issue I just came across, along with a simple solution.

Normally, when you add a RequiredFieldValidator to a form, it triggers when there is an attempted postback for that form. However, I have a scenario where I have two web parts, one called Contact List (this is the provider web part; it simply pulls data from a custom list library called Contact List and displays it) and another web part called Email Contact (this is the consumer webpart; it has a form where a user can enter their name, email, and message they want to email a contact). The Contact List web part provides a person while the Email Contact web part consumes a person. So when a user clicks a person in the Contact List, a postback is performed and the Email Contact web part will display that person's information above the form. A user could then enter their message, then click the Send button and it would email to the selected contact person.

Ok, so did you notice the problem yet? If the Email Contact web part has required field validators on its form fields (ie required on the submitter's name, email, and message), then when a user clicks a person in the Contact List web part, the requiredfieldvalidators in the Email Contact web part will prevent the postback from occurring, thus the person is never sent from the Contact List web part to the Email Contact web part. (Note: this scenario assumed that Contact List and Email Contact are on the same web page in the same WebPartZone).

The solution ended up being pretty simple. I am not going into the details of my specific implementation because the concept here is what it important (plus, I will post the code for this web part anyway in my article on connected web parts that I will do very soon). The solution is to use the ValidationGroup property of the RequiredFieldValidators and the Send button that saves/sends the message. To get this to work, I did the following:

In the Email Contact web part (all this is done in CreateChildControls):
1. create the RequiredFieldValidator controls for each field that needs it
2. add the RequiredFieldValidator controls to the web part's Controls collection
3. set their properties like ErrorMessage and ControlToValidate as you normally would
4. set their ValidationGroup property to "EmailContactValidationGroup"
5. when you create the form's button that saves/sends the email, set the button's ValidationGroup property also to "EmailContactValidationGroup"

The key here is to make sure the ValidationGroup is the same for the button and validators. This way, the validators will only fire off when the button is pressed!