//Ask the user which add-in they would like to use.
AddInToken selectedToken = ChooseAddIn(tokens);

//Activate the selected AddInToken in a new
//application domain with the Internet trust level.
Calculator CalcAddIn = selectedToken.Activate<Calculator>(AddInSecurityLevel.Internet);
            
//Run the add-in using a custom method.
RunCalculator(CalcAddIn);

// Method to select a token by 
// enumeratng the AddInToken collection.
private static AddInToken ChooseAddIn(Collection<AddInToken> tokens)
{
    if (tokens.Count == 0)
    {
        Console.WriteLine("No add-ins are available");
        return null;
    }

    Console.WriteLine("Available add-ins: ");

    // Show the token properties for each token 
    // in the AddInToken collection (tokens),
    // preceded by the add-in number in [] brackets.
    int tokNumber = 1;
    foreach (AddInToken tok in tokens)
    {
        Console.WriteLine(String.Format("\t[{0}]: {1} - {2}\n\t{3}\n\t\t {4}\n\t\t {5} - {6}",
            tokNumber.ToString(), 
            tok.Name,
            tok.AddInFullName,
            tok.AssemblyName,
            tok.Description,
            tok.Version,
            tok.Publisher));
        tokNumber++;
    }

    Console.WriteLine("Which calculator do you want to use?");
    String line = Console.ReadLine();
    int selection;
    if (Int32.TryParse(line, out selection))
    {
        if (selection <= tokens.Count)
        {
            return tokens[selection - 1];
        }
    }
    Console.WriteLine("Invalid selection: {0}. Please choose again.", line);
    return ChooseAddIn(tokens);
}