The IStringList::get_Count method retrieves the number of items in a string list.
HRESULT get_Count(
INT * cStrRet
//pointer to an integer that receives the number of items
);
The Form, QueryString, and ServerVariables collections return parameter values as an array. If the collection does not contain multiple values, the cStrRet will contain 1, if the parameter is not found, it will contain 0.
You can use this method to determine the number of items in the array. For example, if a Form included an Items ordered parameter, you could use the get_Count method to determine the number of items that had been ordered in the Form.
QueryString, Form, ServerVariables