.net Validating a range of controls

I have the following scenario.

I have a search page which is split into two divs. In the first, a user can create query parameters using a range of drop down menus. In the second div a user can enter text to source the query parameter and narrow the search further. On the drop down selectedindex change event, a radio button is selected indicating which search is being looked at.

i.e.

div1 div2

ddl1 tbx1
ddl2 ddl开发者_如何学C4
ddl3
rad1 rad2

Based upon their selection, the user can then click a button, btnReturn, that returns the query.

So therefore, I have the following questions.

1. If I have a range of drop downs, in div1, what sort of validation do I need to set up so that at least one of these drop downs needs to be selected in order for a query to be selected. I cannae just put in required fields as not all of these fields are required, a minium of one of these is need to product a reasonable search.

2. I am assuming I can do all of this using .net validation?

3. I am thinking I can use Validation Groups for div1 & div2 but is it possible to assign both groups to one control i.e. btn click? Is it a case of doing the last part programmatically?

And that concludes today's essay! any help, as always, greatly appreciated.

1. Create a user control (or custom control) wrapping all dropdowns. Then create a Custom Validator, set its validated control to the wrapper you created. Write a javascript function to check that at least one value is selected in the dropdowns and set the ClientValidationFunction property of the custom validator to use it.

2. Yes.

3. No, this wouldn't work in your case (unless you want a postback when switching between the DIVs). Create two submit buttons, and hide them on the client depending on the selected DIV.