CommandApplication

What is it?

An CommandApplication provides a more abstracted way to deal with command line parameters by handling the parsing of the parameters by utilizing attributes. If you use a class derived from CommandApplication, you just have to provide all possible commands your application supports. The input will be processed in the background and will call either the PrintHelpPage or Run method depending if the user selected a HelpOption or not.

The Run method will automatically instantiate and execute the command associated with the StartOptionGroup provided by the user/cli parameters.

Implementation

public abstract class CommandApplication

Constructor

Default constructor that has to be overridden

Methods

Sitnature	Description
public virtual void Run(string[])	Interface between the calling method and the console parameter parsing
protected virtual void PrintHelpPage(ParsedStartOptions)	Called when a HelpOption is selected by the user, processes all selected StartOptions and calls protected abstract void PrintHelpPage
protected abstract void PrintHelpPage(StartOptionParserSettings, IEnumerable<HelpOption>, IEnumerable<StartOptionGroup>, IEnumerable<StartOption>)	Intended for printing a help page for the provided parameters, called by protected virtual void PrintHelpPage
protected abstract void Run(StartOptionGroup, IEnumerable<StartOption>)	Called by public virtual void Run if no HelpOptions are selected by the user. Intended to choose an execution path depending on the provided StartOptionGroup and groupless StartOptions
protected abstract ApplicationStartOptions GetApplicationStartOptions()	Called by the constructor, intended to return an instance of AbstractStartOptions which contains all StartOptionGroups and groupless StartOptions the application should have. Optionally custom HelpOptions and StartOptionParserSettings can be provided in such instance
protected virtual StartOptionParserSettings GetParserSettings()	Provides the StartOptionParserSettings used by the StartOptionParser
protected virtual IEnumerable<HelpOption> GetHelpOptions()	Provides the available HelpOptions for you application
protected abstract Type[] GetCommandTypes()	Provides all command types your application will be able to utilize

Example

class Program
{
    static void Main(string[] args)
    {
        DemoApplication application = new DemoApplication();
        application.Run(args);
        Console.WriteLine("Execution finished");
    }
}

class DemoApplication : CommandApplication
{
    private readonly IHelpPagePrinter helpPrinter = new ConsoleHelpPrinter('\t');

    protected override void PrintHelpPage(StartOptionParserSettings settings, IEnumerable<HelpOption> helpOptions, IEnumerable<StartOptionGroup> groups, IEnumerable<StartOption> grouplessOptions)
    {
        this.helpPrinter.Print(settings, helpOptions, groups, grouplessOptions);
    }

    protected override IEnumerable<HelpOption> GetHelpOptions()
    {
        return new HelpOption[]
        {
            new HelpOption("help", false),
            new HelpOption("h", true)
        };
    }

    protected override StartOptionParserSettings GetParserSettings()
    {
        // Require at least one StartOptionGroup to be provided in the cli arguments
        // Use "/" as prefix for long option names like "/add" or "/help"
        // Use "-" as prefix for short option names like "-a" or "-h"
        // Separate values from the corresponding start option with a space
        // Examples start options: 
        // /> .\StartOptions.Demo.exe /add -1 3 /value-2 5
        // /> .\StartOptions.Demo.exe -h
        return new StartOptionParserSettings()
        {
            RequireStartOptionGroup = true,
            ShortOptionNamePrefix = "-",
            LongOptionNamePrefix = "/",
            OptionValueSeparator = ' ',
        };
    }

    protected override Type[] GetCommandTypes()
    {
        return new[] { typeof(AddCommand), typeof(ReadFileCommand) };
    }
}