Get the Classes List for a Client. 

In this context the term class means an instance where and when training occurs. (As in what occurs in a classroom). This is not to be confused with the notion of a class in software development. 

This is a listing of all Classes (or Instance items) for which the Client is a student in the class, where the class starts within a date range. 

A date range is passed as two parameters, xsdStart and xsdEnd, which define the end points of the date range. These are DateTime objects where the time component is significant. They must be populated with sensible dates (Start > End), otherwise, an input error results. 

Each Instance item is represented by a TInst. The collection of Instance items is represented by a List of TInst. 

A token is passed for authentication. If the authentication fails, or other errors occur, no instance items are returned. The result of the authentication is represented by a TAuthenticate object. 

Requires a valid registration key entry for the Short Courses feature. 

This function has security level "Restricted". Users that have explicitly been granted permission to the API can use it with any parameters, otherwise, the logged-in client can only access their own data.

[WebMethod(Description = "Gets a list of classes (instances) for the client with the specified code in the specified date range")]
public TAuthInstList GetClassesForClient(string sToken, string sClie_Code, DateTime xsdStart, DateTime xsdEnd);