Passing a class as parameter in RESTful WCF Service

In my RESTful WCF Serice I need to pass a class as a parameter for URITemplate. I was able to pass a string or multiple strings as parameters. But I have a lot of fields are there to pass to WCF Service. So I have created a class and added all the fields as properties and then I want to pass this class as one paramenter to the URITemplate. When I am trying to pass class to the URITemplate I am getting error "Path segment must have type string". Its not accepting class as a parameter. Any idea how to pass class as a parameter. Here is my code (inputData is class)

    [OperationContract]
    [WebGet(UriTemplate = "/InsertData/{param1}")]
    string saveData(inputData param1);