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, , 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, );
}
}
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
- 负责配置的加载
- 向VS注册控件
- 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 = ;
} /// <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 >= )
value = ;
_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 > && 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 ==
? 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 < )
return null;
var assemblyName = arr[];
try
{
var assembly = Assembly.Load(assemblyName);
return assembly.CreateInstance(arr[]);
}
catch
{ var file = Path.Combine(Plugin.Location, assemblyName + ".dll");
if (File.Exists(file))
{
var assembly = Assembly.LoadFile(file);
return assembly.CreateInstance(arr[]);
}
}
} 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 == && !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 == )
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
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下篇将以一个实例来讲解框架的使用，敬请期待。