CommandLine

简介

CommandLine 是用于识别解析传入参数的第三方类库，例如dotnet core的发布命令：

dotnet publish -o e:/output

CommandLine 就是用来识别后面的publish，-o等参数的

安装

NuGet Install CommandLineParser

项目地址

GitHub - commandlineparser/commandline: The best C# command line parser that brings standardized *nix getopt style, for .NET. Includes F# support

快速开始

using System;
using CommandLine;

namespace QuickStart
{
    class Program
    {
        public class Options
        {
            [Option('v', "verbose", Required = false, HelpText = "Set output to verbose messages.")]
            public bool Verbose { get; set; }
        }

        static void Main(string[] args)
        {
            Parser.Default.ParseArguments<Options>(args)
                   .WithParsed<Options>(o =>
                   {
                       if (o.Verbose)
                       {
                           Console.WriteLine($"Verbose output enabled. Current Arguments: -v {o.Verbose}");
                           Console.WriteLine("Quick Start Example! App is in Verbose mode!");
                       }
                       else
                       {
                           Console.WriteLine($"Current Arguments: -v {o.Verbose}");
                           Console.WriteLine("Quick Start Example!");
                       }
                   });
        }
    }
}

无动作多参数示例（例如 curl -X xx -H xxx，其中-X xx -H xxx 都是参数，没有动作）

class Options
{
  [Option('r', "read", Required = true, HelpText = "Input files to be processed.")]
  public IEnumerable<string> InputFiles { get; set; }

  // Omitting long name, defaults to name of property, ie "--verbose"
  [Option(
	Default = false,
	HelpText = "Prints all messages to standard output.")]
  public bool Verbose { get; set; }
  
  [Option("stdin",
	Default = false,
	HelpText = "Read from stdin")]
  public bool stdin { get; set; }

  [Value(0, MetaName = "offset", HelpText = "File offset.")]
  public long? Offset { get; set; }
}

static void Main(string[] args)
{
  CommandLine.Parser.Default.ParseArguments<Options>(args)
    .WithParsed(RunOptions)
    .WithNotParsed(HandleParseError);
}
static void RunOptions(Options opts)
{
  //handle options
}
static void HandleParseError(IEnumerable<Error> errs)
{
  //handle errors
}

带动作示例（例如 dotnet publish -o xxx，其中publish就是动作，-o xxx是参数）

[Verb("add", HelpText = "Add file contents to the index.")]
class AddOptions {
  //normal options here
}
[Verb("commit", HelpText = "Record changes to the repository.")]
class CommitOptions {
  //commit options here
}
[Verb("clone", HelpText = "Clone a repository into a new directory.")]
class CloneOptions {
  //clone options here
}

int Main(string[] args) {
  return CommandLine.Parser.Default.ParseArguments<AddOptions, CommitOptions, CloneOptions>(args)
	.MapResult(
	  (AddOptions opts) => RunAddAndReturnExitCode(opts),
	  (CommitOptions opts) => RunCommitAndReturnExitCode(opts),
	  (CloneOptions opts) => RunCloneAndReturnExitCode(opts),
	  errs => 1);
}