Topshelf exception

I'm using topshelf and I'm getting this exception when I try to use the "-i" option to install as a service.

Unable to cast object of type 'Magnum.CommandLineParser.SwitchElement' to type 'Magnum.CommandLineParser.IArgumentElement'.

Exception occurs in this function

static void Set(TopshelfArguments args, 
                IEnumerable<ICommandLineElement> commandLineElements)
{
    var command = commandLineElements
        .Take(1)
        .Select(x => (IArgumentElement) x) //EXCEPTION BREAKS ON THIS LINE开发者_Python百科
        .Select(x => x.Id)
        .DefaultIfEmpty("commandline")
        .SingleOrDefault();

    args.Command = command;
    //leftovers
    args.CommandArgs = commandLineElements.Skip(1).ToList();
}

The way we use TopShelf to install as a service is

program.exe service install

I believe this is the only way it's supported in the RC code. You can uninstall via

program.exe service uninstall

Looks like when passing in -i that the parser is converting it to a type of SwitchElement. Try this to see if it works.

static void Set(TopshelfArguments args, IEnumerable<ICommandLineElement> commandLineElements)
    {
        var command = commandLineElements
            .Take(1)
            .Select(x => (ISwitchElement) x) 
            .Select(x => x.Key)
            .DefaultIfEmpty("commandline")
            .SingleOrDefault();


        args.Command = command;
        //leftovers
        args.CommandArgs = commandLineElements.Skip(1).ToList();
    }