VS2010 Extension实践(1)

最近VS2010 Extension在Visual Studio Blog（http://blogs.msdn.com/visualstudio/）上提得很频繁，于是也想翻来文档研究研究，结果居然找了半天，居然没有一丁点完整介绍这一块的，于是，只好自己找着VS IDE上的模板提供的内容和Visual Studio Blog上的讲解，一边Reflector参演，一边涂鸦一些代码，准备实弹演练一下，但是觉得这个模板建出来的Extension也太简单了，刚好看到AxTool（http://www.axtools.com/products-vs2010-extensions.php）有一个代码编辑器扩展，也是VS Extension的，于是就照着这个，自己一步一步做一下。

首先，要想建立VS Extension工程，你需要安装VS2010 SDK，目前是Beta2版本，你可以到这里可以下载：http://go.microsoft.com/fwlink/?LinkID=165597），这里我是通过Editor Text Adornment模板创建的工程，嗯，我就不详细写如何通过模板创建自己Extension工程了，如果你不熟悉这里，可以参考Quan To的这篇帖子——Building and publishing an extension for Visual Studio 2010。

建好工程以后，会自动生成TextViewCreationListener，这里实现了IWpfTextViewCreationListener接口，并通过MEF导出IWpfTextViewCreationListener对象：

[TextViewRole("DOCUMENT")]
[Export(typeof(IWpfTextViewCreationListener))]
[ContentType("text")]
internal sealed class PETextViewCreationListener : IWpfTextViewCreationListener    
{
        void IWpfTextViewCreationListener.TextViewCreated(IWpfTextView textView)
        {
            //...
        }
}

这样VS就会在合适的时候调用IWpfTextViewCreationListener.TextViewCreated方法来通知文字编辑的状态改变。

为了实现浮动一个自己的工具栏，这里还需要导出一个AdornmentLayerDefinition，并通过Order Attribute来定制这个Adornment层的显示位置和次序：

[Name("QuickToolbarAdornmentLayer")]
[Order(After = "Text")]
[Export(typeof(AdornmentLayerDefinition))]
public AdornmentLayerDefinition QuickToolbarLayerDefinition
{
    get;
    set;
}

这里的Name Attribute很重要，以后的代码中要获取我们的AdornmentLayer就得靠它了：

1	`this._adornmentLayer =` `this._textView.GetAdornmentLayer("QuickToolbarAdornmentLayer");`

扯得远了，回到IWpfTextViewCreationListener.TextViewCreated，通过这里，可以得到一个IWpfTextView，

这是所有操作的目标和展现，另外，还需要挂他的Closed、LayoutChanged、MouseHovered、SelectionChanged等事件，以响应用户行为。

由于我们要通过工具栏操作代码，所以需要通过MEF导入IEditorOperationsFactoryService：

[Import]
internal IEditorOperationsFactoryService EditorOperationsFactoryService
{
    get;
    set;
}

这样就可以在IWpfTextViewCreationListener.TextViewCreated中通过IEditorOperationsFactoryService.GetEditorOperations(ITextView)来获得IEditorOperations，有了它，就可以方便快捷的编辑代码了。

接下来要实现工具栏的界面，这个就不多说了，建一个UserControl，里面放上ToolBar就搞定了。那么何时何地显示这个ToolBar呢？这就要依赖IWpfTextView的SelectionChanged事件了，上面提到会挂这个事件就是为这里用的。

1                 private void MayBeAdornmentShowCondition()
 2                 {
 3                     if (!this._textView.Selection.IsEmpty)
 4                     {
 5                         SnapshotPoint startPos = this._textView.Selection.Start.Position;
 6                         SnapshotPoint endPos = this._textView.Selection.End.Position;
 7                         IWpfTextViewLine textViewLineContainingBufferPosition = this._textView.GetTextViewLineContainingBufferPosition(startPos);
 8                         TextBounds characterBounds = textViewLineContainingBufferPosition.GetCharacterBounds(startPos);
 9                         TextBounds bounds2 = this._textView.GetTextViewLineContainingBufferPosition(endPos).GetCharacterBounds(endPos);
10                         if (this._fromMouseHover)
11                         {
12                             this._mustHaveAdornmentDisplayed = true;
13                         }
14                         else
15                         {
16                             PELeftButtonMouseProcessor property = null;
17                             try
18                             {
19                                 property = this._textView.Properties.GetProperty<PELeftButtonMouseProcessor>(typeof(PELeftButtonMouseProcessor));
20                             }
21                             catch
22                             {
23                             }
24                             this._mustHaveAdornmentDisplayed = (property != null)
25                                 && (property.IsLeftButtonDown
26                                 || ((DateTime.Now - property.LastLeftButtonDownTime).TotalMilliseconds < 400.0));
27                         }
28                         if (this._mustHaveAdornmentDisplayed)
29                         {
30                             TextBounds selectionBounds = !this._textView.Selection.IsReversed ? bounds2 : characterBounds;
31                             int offset = 7;
32                             double top = selectionBounds.Top + (!this._textView.Selection.IsReversed ? (offset + textViewLineContainingBufferPosition.Height) : (-offset - this._adornmentUI.ActualHeight));
33                             if (top < 0.0)
34                             {
35                                 top = 0.0;
36                             }
37                             double left = characterBounds.Left + ((bounds2.Left - characterBounds.Left) / 2.0);
38                             if ((left + this._adornmentUI.ActualWidth) > this._textView.ViewportWidth)
39                             {
40                                 left = this._textView.ViewportWidth - this._adornmentUI.ActualWidth;
41                             }
42                             Canvas.SetTop(this._adornmentUI, top);
43                             Canvas.SetLeft(this._adornmentUI, left);
44                             long chars = 0L;
45                             try
46                             {
47                                 chars = this._textView.Selection.SelectedSpans[0].Span.Length;
48                             }
49                             catch
50                             {
51                             }
52                             this._adornmentUI.SetStatus(chars);
53                             this.RenderSelectionPopup();
54                         }
55                     }
56                     else
57                     {
58                         this._mustHaveAdornmentDisplayed = false;
59                         this._adornmentLayer.RemoveAdornmentsByTag(this._adornmentTag);
60                     }
61                 }
62 
63                 private void RenderSelectionPopup()
64                 {
65                     if (this._mustHaveAdornmentDisplayed)
66                     {
67                         IAdornmentLayerElement element = null;
68                         try
69                         {
70                             element = this._adornmentLayer.Elements.First<IAdornmentLayerElement>(
71                                 (IAdornmentLayerElement ile) => ile.Tag.ToString() == this._adornmentTag);
72                         }
73                         catch (InvalidOperationException)
74                         {
75                         }
76                         if (element == null)
77                         {
78                             this._adornmentLayer.AddAdornment(this._textView.Selection.SelectedSpans[0], this._adornmentTag, this._adornmentUI);
79                         }
80                         this._timer.Stop();
81                         this._timer.Start();
82                     }
83                 }
84 
85                 private void selection_SelectionChanged(object sender, EventArgs e)
86                 {
87                     this._fromMouseHover = false;
88                     this.MayBeAdornmentShowCondition();
89                 }