在构建接受参数的控制台应用程序时,可以使用传递给Main的参数(string[] args)。

在过去,我只是简单地索引/循环该数组,并做了一些正则表达式来提取值。然而,当命令变得更加复杂时,解析就会变得非常糟糕。

我感兴趣的是:

你使用的库 你使用的模式

假设命令总是遵循常见的标准,比如这里回答的。


当前回答

Genghis命令行解析器可能有点过时,但它的功能非常完整,对我来说工作得很好。

其他回答

我个人最喜欢的是Peter palota的http://www.codeproject.com/KB/recipes/plossum_commandline.aspx:

[CommandLineManager(ApplicationName="Hello World",
    Copyright="Copyright (c) Peter Palotas")]
class Options
{
   [CommandLineOption(Description="Displays this help text")]
   public bool Help = false;

   [CommandLineOption(Description = "Specifies the input file", MinOccurs=1)]
   public string Name
   {
      get { return mName; }
      set
      {
         if (String.IsNullOrEmpty(value))
            throw new InvalidOptionValueException(
                "The name must not be empty", false);
         mName = value;
      }
   }

   private string mName;
}

我强烈建议使用NDesk。选项(文档)和/或Mono。选项(相同的API,不同的名称空间)。文档中的一个例子:

bool show_help = false;
List<string> names = new List<string> ();
int repeat = 1;

var p = new OptionSet () {
    { "n|name=", "the {NAME} of someone to greet.",
       v => names.Add (v) },
    { "r|repeat=", 
       "the number of {TIMES} to repeat the greeting.\n" + 
          "this must be an integer.",
        (int v) => repeat = v },
    { "v", "increase debug message verbosity",
       v => { if (v != null) ++verbosity; } },
    { "h|help",  "show this message and exit", 
       v => show_help = v != null },
};

List<string> extra;
try {
    extra = p.Parse (args);
}
catch (OptionException e) {
    Console.Write ("greet: ");
    Console.WriteLine (e.Message);
    Console.WriteLine ("Try `greet --help' for more information.");
    return;
}

我最近遇到了FubuCore命令行解析实现,我真的很喜欢它,原因是:

it's easy to use - although I couldn't find a documentation for it, the FubuCore solution also provides a project containing a nice set of Unit Tests that speak more about the functionality than any documentation could it has a nice object oriented design, no code repetition or other such things that I used to have in my command line parsing apps it's declarative: you basically write classes for the Commands and sets of parameters and decorate them with attributes to set various options (e.g. name, description, mandatory/optional) the library even prints a nice Usage Graph, based on these definitions

下面是一个简单的例子说明如何使用它。为了说明用法,我写了一个简单的实用程序,它有两个命令: - add(将一个对象添加到列表中-一个对象由一个名称(字符串),值(int)和一个布尔标志组成) - list(列出当前添加的所有对象)

首先,我为'add'命令写了一个Command类:

[Usage("add", "Adds an object to the list")]
[CommandDescription("Add object", Name = "add")]
public class AddCommand : FubuCommand<CommandInput>
{
    public override bool Execute(CommandInput input)
    {
        State.Objects.Add(input); // add the new object to an in-memory collection

        return true;
    }
}

这个命令接受一个commandput实例作为参数,所以我下面定义它:

public class CommandInput
{
    [RequiredUsage("add"), Description("The name of the object to add")]
    public string ObjectName { get; set; }

    [ValidUsage("add")]
    [Description("The value of the object to add")]
    public int ObjectValue { get; set; }

    [Description("Multiply the value by -1")]
    [ValidUsage("add")]
    [FlagAlias("nv")]
    public bool NegateValueFlag { get; set; }
}

下一个命令是'list',实现如下:

[Usage("list", "List the objects we have so far")]
[CommandDescription("List objects", Name = "list")]
public class ListCommand : FubuCommand<NullInput>
{
    public override bool Execute(NullInput input)
    {
        State.Objects.ForEach(Console.WriteLine);

        return false;
    }
}

'list'命令不带参数,所以我定义了一个NullInput类:

public class NullInput { }

现在剩下的就是在Main()方法中把它连接起来,就像这样:

    static void Main(string[] args)
    {
        var factory = new CommandFactory();
        factory.RegisterCommands(typeof(Program).Assembly);

        var executor = new CommandExecutor(factory);

        executor.Execute(args);
    }

程序按预期工作,在任何命令无效的情况下打印正确用法的提示:

  ------------------------
    Available commands:
  ------------------------
     add -> Add object
    list -> List objects
  ------------------------

下面是'add'命令的用法示例:

Usages for 'add' (Add object)
  add <objectname> [-nv]

  -------------------------------------------------
    Arguments
  -------------------------------------------------
     objectname -> The name of the object to add
    objectvalue -> The value of the object to add
  -------------------------------------------------

  -------------------------------------
    Flags
  -------------------------------------
    [-nv] -> Multiply the value by -1
  -------------------------------------

看看http://github.com/mono/mono/tree/master/mcs/class/Mono.Options/

这是我基于Novell Options类编写的处理程序。

它针对的是执行while (input !="exit")样式循环的控制台应用程序,例如一个交互式控制台,例如FTP控制台。

使用示例:

static void Main(string[] args)
{
    // Setup
    CommandHandler handler = new CommandHandler();
    CommandOptions options = new CommandOptions();

    // Add some commands. Use the v syntax for passing arguments
    options.Add("show", handler.Show)
        .Add("connect", v => handler.Connect(v))
        .Add("dir", handler.Dir);

    // Read lines
    System.Console.Write(">");
    string input = System.Console.ReadLine();

    while (input != "quit" && input != "exit")
    {
        if (input == "cls" || input == "clear")
        {
            System.Console.Clear();
        }
        else
        {
            if (!string.IsNullOrEmpty(input))
            {
                if (options.Parse(input))
                {
                    System.Console.WriteLine(handler.OutputMessage);
                }
                else
                {
                    System.Console.WriteLine("I didn't understand that command");
                }

            }

        }

        System.Console.Write(">");
        input = System.Console.ReadLine();
    }
}

来源是:

/// <summary>
/// A class for parsing commands inside a tool. Based on Novell Options class (http://www.ndesk.org/Options).
/// </summary>
public class CommandOptions
{
    private Dictionary<string, Action<string[]>> _actions;
    private Dictionary<string, Action> _actionsNoParams;

    /// <summary>
    /// Initializes a new instance of the <see cref="CommandOptions"/> class.
    /// </summary>
    public CommandOptions()
    {
        _actions = new Dictionary<string, Action<string[]>>();
        _actionsNoParams = new Dictionary<string, Action>();
    }

    /// <summary>
    /// Adds a command option and an action to perform when the command is found.
    /// </summary>
    /// <param name="name">The name of the command.</param>
    /// <param name="action">An action delegate</param>
    /// <returns>The current CommandOptions instance.</returns>
    public CommandOptions Add(string name, Action action)
    {
        _actionsNoParams.Add(name, action);
        return this;
    }

    /// <summary>
    /// Adds a command option and an action (with parameter) to perform when the command is found.
    /// </summary>
    /// <param name="name">The name of the command.</param>
    /// <param name="action">An action delegate that has one parameter - string[] args.</param>
    /// <returns>The current CommandOptions instance.</returns>
    public CommandOptions Add(string name, Action<string[]> action)
    {
        _actions.Add(name, action);
        return this;
    }

    /// <summary>
    /// Parses the text command and calls any actions associated with the command.
    /// </summary>
    /// <param name="command">The text command, e.g "show databases"</param>
    public bool Parse(string command)
    {
        if (command.IndexOf(" ") == -1)
        {
            // No params
            foreach (string key in _actionsNoParams.Keys)
            {
                if (command == key)
                {
                    _actionsNoParams[key].Invoke();
                    return true;
                }
            }
        }
        else
        {
            // Params
            foreach (string key in _actions.Keys)
            {
                if (command.StartsWith(key) && command.Length > key.Length)
                {

                    string options = command.Substring(key.Length);
                    options = options.Trim();
                    string[] parts = options.Split(' ');
                    _actions[key].Invoke(parts);
                    return true;
                }
            }
        }

        return false;
    }
}