VsSharp：一个VS扩展开发框架（上）

上篇：设计

一、引子

自2008年起开发SSMS插件SqlSharp(er)的过程中，有一天发现多数代码都大同小异，就像这样。

 Commands2 commands = (Commands2)_applicationObject.Commands;
                string toolsMenuName = "Tools";

                //Place the command on the tools menu.
                //Find the MenuBar command bar, which is the top-level command bar holding all the main menu items:
                Microsoft.VisualStudio.CommandBars.CommandBar menuBarCommandBar = ((Microsoft.VisualStudio.CommandBars.CommandBars)_applicationObject.CommandBars)["MenuBar"];

                //Find the Tools command bar on the MenuBar command bar:
                CommandBarControl toolsControl = menuBarCommandBar.Controls[toolsMenuName];
                CommandBarPopup toolsPopup = (CommandBarPopup)toolsControl;

                //This try/catch block can be duplicated if you wish to add multiple commands to be handled by your Add-in,
                //  just make sure you also update the QueryStatus/Exec method to include the new command names.
                try
                {
                    //Add a command to the Commands collection:
                    // add + (int)vsCommandStatus.vsCommandStatusEnabled if we want the default state to be enabled
                    Command command = commands.AddNamedCommand2(_addInInstance, "FormatSQL", "Format SQL", "Format SQL", true, 59, ref contextGUIDS, (int)vsCommandStatus.vsCommandStatusSupported + (int)vsCommandStatus.vsCommandStatusEnabled, (int)vsCommandStyle.vsCommandStylePictAndText, vsCommandControlType.vsCommandControlTypeButton);

                    //Add a control for the command to the tools menu:
                    if ((command != null) && (toolsPopup != null))
                    {
                        command.AddControl(toolsPopup.CommandBar, 1);
                    }
                }
                catch (System.ArgumentException)
                {
                    //If we are here, then the exception is probably because a command with that name
                    //  already exists. If so there is no need to recreate the command and we can 
                    //  safely ignore the exception.
                }

于是萌生出开发一个框架的想法。

于是有了一个叫SsmsSharp的框架，后正式命名为SqlSharp发布到了CodePlex上。

与此同时，将操纵EnvDTE的代码与SSMS Objects的代码分离，操纵EnvDTE的代码就形成了本篇要说的VsSharp。

后来，当我正式使用VsSharp开发VS扩展时，又引出一些新问题如源代码签出、一个VS搭载多个扩展，解决这些问题后，VsSharp开始成熟起来。

二、设计思路

1、目标

应用Command模式，定义每个控件的行为。将一个个控件的属性与行为集合在一个配置文件中，在VS启动时自动加载控件，点击控件时通过反射触发相应的命令。

2、流程

User：终端用户（也就是各位码农）

Host：VS实例，提供全局的EnvDTE对象访问器，注册Plugin，响应IDE的各种事件（如文档打开关闭等）

Plugin：基于VsSharp开发的插件（此处为避免与EnvDTE.AddIn重名，命名为Plugin)

由此引出VsSharp的职责

1. 负责配置的加载
2. 向VS注册控件
3. 响应用户的点击及其他事件

三、概要设计

1、对象设计

    1.1 基于上述职责定义，抽象出如下对象：

• CommandConfig:负责命令与控件的配置描述
• CommandManager：负责配置的加载，和与VS的交互
• CommandBarAccessor：与VS直接交互的对象，实现ICommandBarAccessor接口，主要是为了隔离VS版本的差异
• Host：宿主，单例，表示当前操作的VS实例；CommandAccessor通过它与EnvDTE交互
• PlugIn：主要属性为CommandConfig和Connect入口的Assembly

   CommandBarAccessor的行为：

 public interface ICommandBarAccessor
    {
        void AddControl(CommandControl control);
        void ResetControl(CommandControl control);
        void EnableControls(IEnumerable<string> ids ,bool enabled);
        void Delete();
    }

• AddContro:添加一个控件
• ResetControl:重置控件，比如某控件的子菜单可以依赖于特定的配置或数据源，当配置或数据源发生变化时，需要重新加载控件
• EnableControl:启用（禁用）控件，比如某些控件是用于操作文档的，当有文档打开时才启用
• Delete：删除控件，当VS退出时执行Disconnect方法时触发

    1.2 命令接口

 public interface ICommand
    {
        void Execute(object arg = null);
    }

   命令类型：

 public enum CommandActionType
    {
        Menu,
        Program,
        Window,
        Dialog
    }

• Menu：缺省类型，无任何行为
• Program:执行一段程序
• Window：打开一个窗体
• Dialog：打开一个模态窗体

    1.3 命令控件描述

      主要有两种控件类型：

• CommandMenu：包括主菜单栏的自定义菜单、上下文菜单，其下级可以有子菜单
• CommandButton：主要是插入ToolStrip的ToolStripButton，其下级也可以有子菜单

     抽象类CommandControl：CommandMenu和CommandButton的父类，描述控件的ID、文本、图标、命令类型、位置、所属父控件等属性。

以下代码段为CommandControl的全部属性。

其中，

ClassName为供反射用的动作类型名称，当CommandActionType为Program时，要求该类型实现了ICommand接口。

public abstract class CommandControl
    {
        private Form _form;
        private int _position;
        private Image _image;
        private string _arg;
        private ICommand _command;

        /// <summary>
        /// Constructor
        /// </summary>
        protected CommandControl()
        {
            CommandActionType = CommandActionType.Menu;
            Position = 1;
        }

        /// <summary>
        /// Id,as while as the command Name
        /// </summary>
        [XmlAttribute("id")]
        public string Id { get; set; }

        /// <summary>
        /// Text
        /// </summary>
        [XmlAttribute("text")]
        public string Text { get; set; }

        /// <summary>
        /// Tooltip text
        /// </summary>
        [XmlAttribute("tooltip")]
        public string Tooltip { get; set; }

        /// <summary>
        /// Office style icon face id
        /// </summary>
        [XmlAttribute("faceId")]
        public int FaceId { get; set; }

        /// <summary>
        ///   Relative position in the parent control,can be minus
        /// </summary>
        /// <remarks>
        /// 相对于父控件Child总数n而言，大于等于0则放在末尾n+1的位置，为负数则放在倒数第n-Position的位置
        /// </remarks>
        [XmlAttribute("position")]
        public int Position
        {
            get { return _position; }
            set
            {
                if (value >= 0)
                    value = 1;
                _position = value;
            }
        }

        /// <summary>
        /// Picture id in ResourceManager
        /// </summary>
        [XmlAttribute("picture")]
        public string Picture { get; set; }

        [XmlIgnore]
        public StdPicture StdPicture
        {
            get
            {
                if (!String.IsNullOrEmpty(Picture) && Plugin != null && Plugin.ResourceManager != null)
                {
                    return Plugin.ResourceManager.LoadPicture(Picture);
                }
                return null;
            }
        }

        /// <summary>
        /// Image instance from ResourceManager
        /// </summary>
        [XmlIgnore]
        public Image Image
        {
            get
            {
                if (_image == null && !string.IsNullOrEmpty(Picture) && Picture.Trim().Length > 0 && Plugin != null && Plugin.ResourceManager != null)
                {
                    _image = Plugin.ResourceManager.LoadBitmap(Picture);
                }
                return _image;
            }
            set
            {
                _image = value;
            }
        }


        /// <summary>
        /// Action class type name
        /// </summary>
        [XmlAttribute("class")]
        public string ClassName { get; set; }

        /// <summary>
        /// Action type
        /// </summary>
        [XmlAttribute("type")]
        public CommandActionType CommandActionType { get; set; }

        /// <summary>
        /// Parent control name that the control attach to
        /// </summary>
        [XmlAttribute("attachTo")]
        public string AttachTo { get; set; }

        //[XmlAttribute("hotKey")]
        //public string HotKey { get; set; }

        /// <summary>
        /// begin group,insert a bar in context menu if set True
        /// </summary>
        [XmlAttribute("beginGroup")]
        public bool BeginGroup { get; set; }

        /// <summary>
        /// Command instance of <see cref="ClassName"/>
        /// </summary>
        [XmlIgnore]
        public ICommand Command
        {
            get { return _command ?? (_command = LoadInstance(ClassName) as ICommand); }
            set { _command = value; }
        }

        /// <summary>
        /// <see cref="Plugin"/> which the control attach to
        /// </summary>
        [XmlIgnore]
        public Plugin Plugin { get; set; }


        /// <summary>
        /// Argument for <see cref="ICommand"/> execution
        /// </summary>
        [XmlAttribute("arg")]
        public string Arg
        {
            get { return _arg; }
            set
            {
                _arg = value;
                Tag = _arg;
              
            }
        }

        /// <summary>
        /// <see cref="DependentItems"/> name for making the control  enabled or disabled
        /// </summary>
        [XmlAttribute("dependOn")]
        public string DependOn { get; set; }

          [XmlIgnore]
        public DependentItems DependentItems {
              get
              {
                  return string.IsNullOrEmpty(DependOn) || DependOn.Trim().Length == 0
                      ? DependentItems.None
                      : (DependentItems)Enum.Parse(typeof(DependentItems), DependOn);
              } }

        /// <summary>
          /// Argument for <see cref="ICommand"/> execution,only be assgined by programming
        /// </summary>
        [XmlIgnore]
        public object Tag { get; set; }

        public override string ToString()
        {
            return Text;
        }

        /// <summary>
        /// execute action
        /// </summary>
        public virtual void Execute()
        {
            var arg = Arg ?? Tag;
            switch (CommandActionType)
            {
                case CommandActionType.Program:
                    if (Command != null)
                    {
                        Command.Execute(arg);
                    }
                    break;
                case CommandActionType.Window:
                    var window = GetForm();
                    window.Show();
                    break;
                case CommandActionType.Dialog:
                    var dialog = GetForm();
                    dialog.ShowDialog();
                    break;
            }
        }

        /// <summary>
        /// load an instance
        /// </summary>
        /// <param name="typeName"></param>
        /// <returns></returns>
        public object LoadInstance(string typeName)
        {
            if (typeName.Contains(","))
            {
                var arr = typeName.Split(',');
                if (arr.Length < 2)
                    return null;
                var assemblyName = arr[1];
                try
                {
                    var assembly = Assembly.Load(assemblyName);
                    return assembly.CreateInstance(arr[0]);
                }
                catch
                {

                    var file = Path.Combine(Plugin.Location, assemblyName + ".dll");
                    if (File.Exists(file))
                    {
                        var assembly = Assembly.LoadFile(file);
                        return assembly.CreateInstance(arr[0]);
                    }
                }
            }


            return Plugin.Assembly.CreateInstance(typeName);

        }

        private Form GetForm()
        {
            if (_form != null && !_form.IsDisposed)
                return _form;
            _form = (Form)LoadInstance(ClassName);
            return _form;
        }
    }

CommandMenu继承CommandControl，特有子菜单相关属性。

其中SubMenus属性可在编程时操纵，SubGeneratorType为配置文件中定义的供反射用的子菜单生成器类型，用于启动时根据特定数据源自动生成。

 public class CommandMenu : CommandControl
    {
        private List<CommandMenu> _subMenus;

        public CommandMenu()
        {
            _subMenus = new List<CommandMenu>();
        }

        [XmlElement("menu")]
        public List<CommandMenu> SubMenus
        {
            get
            {
                if (_subMenus.Count == 0 && !string.IsNullOrEmpty(SubGeneratorType))
                {
                    LoadSubMenus();
                }
                return _subMenus;
            }
            set { _subMenus = value; }
        }

        [XmlAttribute("sgt")]
        public string SubGeneratorType { get; set; }

        protected virtual IEnumerable<CommandMenu> GenerateSubMenus()
        {
            if (string.IsNullOrEmpty(SubGeneratorType) || SubGeneratorType.Trim().Length == 0)
                return null;
            var gen = LoadInstance(SubGeneratorType) as ICommandMenuGenerator;
            if (gen == null)
                return null;
            return gen.Generate();
        }

        public virtual void LoadSubMenus()
        {
            if (GenerateSubMenus() == null)
                return;
            _subMenus = GenerateSubMenus().ToList();
        }

    }

2、类图

 调用关系 ：

• Connect对象启动时加载CommandConfig，生成一个Plugin对象传给CommandManager，并向Host.Instance注册；CommandManager加载CommandConfig描述的所有控件
• Connect.OnConnection方法调用CommandManager.Load方法
• Connect.Exec方法调用CommandManager.Execute方法
• Connect.OnDisconnection方法调用CommandManager.Disconnect方法

四、源代码

http://vssharp.codeplex.com/

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下篇将以一个实例来讲解框架的使用，敬请期待。