Pass Variables in a Query String?

Hi,

What is the best way to pass variables from page to page (template to template) in Silverstripe?

I'm on a page which lists clients, and I want to click on the client and pass that client's name to a page whose controller takes the name and get all the projects for that particular client from the database.

The link is "projects-by-client?Client=Client1". In my ProjectsByClient controller, I have the following function:

function ProjectsByClient($Client) {
$whereStatement = "ProjectClient = '".$Client."'";
return DataObject::get("ProjectPage", $whereStatement);
}

Thwe query works fine if you hard-code a client name. But my controller is saying "missing argument" when I try to pass it in dynamically. How can I pass the client name to the controller?? Seems like this should be easy.

Thanks in advance,
Garrett