c# - Visual Studio拦截F1帮助命令

Question

我希望编写一个Visual Studio插件，该插件可以拦截默认的联机帮助命令，并在类或类型上调用F1帮助时获取MSDN库URL。

例如，说我将光标放在关键字字符串上，然后按F1键，它通常会自动打开浏览器并导航到该字符串引用类型的帮助文档。我想在传递给浏览器的URL到达浏览器之前对其进行抓取。

是否可以编写可以拦截默认F1帮助命令的Visual Studio外接程序/扩展程序？

如果可以完成上述操作，那么有关从何处开始的任何指针？

Answer 1

大约10年前，当我在Microsoft工作时，我在Visual Studio 2005中为原始的“Online F1”功能编写了规范。因此，我的知识虽然有些权威，但可能已经过时了。 ;-)

您无法更改Visual Studio使用的URL(至少我不知道如何更改)，但是您可以简单地编写另一个插件来窃取F1键绑定(bind)，并使用与默认设置相同的帮助上下文。 F1处理程序会执行此操作，并将用户定向到您自己的URL或应用程序。

首先，有关Online F1工作原理的一些信息:

Visual Studio IDE的

组件将关键字推送到“F1帮助上下文”中，该上下文是有关用户正在执行的操作的信息的属性包:代码编辑器中的当前选择，正在编辑的文件类型，正在编辑的项目类型等。

当用户按下F1时，IDE会将帮助上下文打包到URL中，并打开指向MSDN的浏览器。

选择CSS属性“宽度”时，按在VS2012的HTML编辑器F1的时候，这里是一个示例URL，在这种情况下，

msdn.microsoft.com/query/dev11.query?
    appId=Dev11IDEF1&
    l=EN-US&
    k=k(width);
        k(vs.csseditor);
        k(TargetFrameworkMoniker-.NETFramework,Version%3Dv4.0);
        k(DevLang-CSS)&
    rd=true

上面的“k”参数包含Visual Studio内部的帮助上下文。帮助上下文同时包含“关键字”(文本字符串)和“属性”(名称/值对)，Visual Studio内部的各种窗口都使用它们来告知IDE用户当前正在做什么。

CSS编辑器推送了两个关键字:我选择的“宽度”和“vs.csseditor”，如果例如在MSDN上找不到我的选择，则MSDN可以将其用作“后备”。

还有一些上下文过滤属性:

TargetFrameworkMoniker = NETFramework,Version=v4.0
DevLang=CSS

这些确保F1以正确的语言或技术(在本例中为CSS)加载页面。 (存在另一个针对.NET 4.0的过滤器，因为我加载的项目针对的是.NET 4.0)

注意上下文是有序的。 “宽度”关键字比下方的关键字重要。

MSDN上的实际帮助内容具有元数据(由编写文档的团队手动设置)，该元数据包含与该页面关联的关键字和名称/值上下文属性。例如，当MSDN上的 css width property documentation存储在MSDN服务器上时，它具有与之关联的关键字列表(在本例中为“width”)和上下文属性的列表在本例中为“DevLang = CSS”。页面可以具有多个关键字(例如“System.String”，“String”)和多个上下文属性(例如“DevLang = C#”，“DevLang = VB”等)。

当关键字列表进入MSDN Online F1服务时，该算法是这样的，但需要注意的是，在最近几年中它可能已更改:

使用第一个关键字

查找与该关键字

匹配的所有页面

排除所有与上下文属性名称匹配的页面(例如“DevLang”)，但与值不匹配的所有页面。例如，这将排除Control.Width页面，因为它将被标记为“DevLang = C#”，“DevLang = VB”。但是它不会排除没有DevLang属性的页面。

如果没有结果，但是还有更多的关键字可使用，除非您用尽了所有关键字，否则请从＃1重新开始使用下一个关键字(按顺序)。如果没有关键字，请执行“备份”操作，这可能会返回MSDN搜索结果列表，可能会显示“找不到页面”或其他解决方案。

对其余结果进行排名。我不记得确切的排名算法，并且此后可能会发生变化，但是我相信总体思路是先显示匹配更多属性的页面，然后再显示更受欢迎的匹配项。

在浏览器中显示最高结果

这是有关Visual Studio外接程序如何执行的代码示例:

接管F1键绑定(bind)

按下F1时

，获取帮助上下文并将其转换为一组名称=值对

将那组“名称=值”对传递给一些外部代码，以对F1请求进行处理。

我遗漏了所有Visual Studio外接程序样板代码-如果您也需要这样做，那么Google中应该有很多示例。

using System;
using Extensibility;
using EnvDTE;
using EnvDTE80;
using Microsoft.VisualStudio.CommandBars;
using System.Resources;
using System.Reflection;
using System.Globalization;
using System.Collections;
using System.Collections.Generic;
using System.Text;

namespace ReplaceF1
{
    /// <summary>The object for implementing an Add-in.</summary>
    /// <seealso class='IDTExtensibility2' />
    public class Connect : IDTExtensibility2, IDTCommandTarget
    {
        /// <summary>Implements the constructor for the Add-in object. Place your initialization code within this method.</summary>
        public Connect()
        {
        }

        MsdnExplorer.MainWindow Explorer = new MsdnExplorer.MainWindow();

        /// <summary>Implements the OnConnection method of the IDTExtensibility2 interface. Receives notification that the Add-in is being loaded.</summary>
        /// <param term='application'>Root object of the host application.</param>
        /// <param term='connectMode'>Describes how the Add-in is being loaded.</param>
        /// <param term='addInInst'>Object representing this Add-in.</param>
        /// <seealso class='IDTExtensibility2' />
        public void OnConnection(object application, ext_ConnectMode connectMode, object addInInst, ref Array custom)
        {
            _applicationObject = (DTE2)application;
            _addInInstance = (AddIn)addInInst;
            if(connectMode == ext_ConnectMode.ext_cm_UISetup)
            {
                object []contextGUIDS = new object[] { };
                Commands2 commands = (Commands2)_applicationObject.Commands;
                string toolsMenuName;

                try
                {
                    // If you would like to move the command to a different menu, change the word "Help" to the 
                    //  English version of the menu. This code will take the culture, append on the name of the menu
                    //  then add the command to that menu. You can find a list of all the top-level menus in the file
                    //  CommandBar.resx.
                    ResourceManager resourceManager = new ResourceManager("ReplaceF1.CommandBar", Assembly.GetExecutingAssembly());
                    CultureInfo cultureInfo = new System.Globalization.CultureInfo(_applicationObject.LocaleID);
                    string resourceName = String.Concat(cultureInfo.TwoLetterISOLanguageName, "Help");
                    toolsMenuName = resourceManager.GetString(resourceName);
                }
                catch
                {
                    //We tried to find a localized version of the word Tools, but one was not found.
                    //  Default to the en-US word, which may work for the current culture.
                    toolsMenuName = "Help";
                }

                //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:
                    Command command = commands.AddNamedCommand2(_addInInstance, 
                        "ReplaceF1", 
                        "MSDN Advanced F1", 
                        "Brings up context-sensitive Help via the MSDN Add-in", 
                        true, 
                        59, 
                        ref contextGUIDS, 
                        (int)vsCommandStatus.vsCommandStatusSupported+(int)vsCommandStatus.vsCommandStatusEnabled, 
                        (int)vsCommandStyle.vsCommandStylePictAndText, 
                        vsCommandControlType.vsCommandControlTypeButton);
                    command.Bindings = new object[] { "Global::F1" };
                }
                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.
                }
            }
        }

        /// <summary>Implements the OnDisconnection method of the IDTExtensibility2 interface. Receives notification that the Add-in is being unloaded.</summary>
        /// <param term='disconnectMode'>Describes how the Add-in is being unloaded.</param>
        /// <param term='custom'>Array of parameters that are host application specific.</param>
        /// <seealso class='IDTExtensibility2' />
        public void OnDisconnection(ext_DisconnectMode disconnectMode, ref Array custom)
        {
        }

        /// <summary>Implements the OnAddInsUpdate method of the IDTExtensibility2 interface. Receives notification when the collection of Add-ins has changed.</summary>
        /// <param term='custom'>Array of parameters that are host application specific.</param>
        /// <seealso class='IDTExtensibility2' />       
        public void OnAddInsUpdate(ref Array custom)
        {
        }

        /// <summary>Implements the OnStartupComplete method of the IDTExtensibility2 interface. Receives notification that the host application has completed loading.</summary>
        /// <param term='custom'>Array of parameters that are host application specific.</param>
        /// <seealso class='IDTExtensibility2' />
        public void OnStartupComplete(ref Array custom)
        {
        }

        /// <summary>Implements the OnBeginShutdown method of the IDTExtensibility2 interface. Receives notification that the host application is being unloaded.</summary>
        /// <param term='custom'>Array of parameters that are host application specific.</param>
        /// <seealso class='IDTExtensibility2' />
        public void OnBeginShutdown(ref Array custom)
        {
        }

        /// <summary>Implements the QueryStatus method of the IDTCommandTarget interface. This is called when the command's availability is updated</summary>
        /// <param term='commandName'>The name of the command to determine state for.</param>
        /// <param term='neededText'>Text that is needed for the command.</param>
        /// <param term='status'>The state of the command in the user interface.</param>
        /// <param term='commandText'>Text requested by the neededText parameter.</param>
        /// <seealso class='Exec' />
        public void QueryStatus(string commandName, vsCommandStatusTextWanted neededText, ref vsCommandStatus status, ref object commandText)
        {
            if(neededText == vsCommandStatusTextWanted.vsCommandStatusTextWantedNone)
            {
                if(commandName == "ReplaceF1.Connect.ReplaceF1")
                {
                    status = (vsCommandStatus)vsCommandStatus.vsCommandStatusSupported|vsCommandStatus.vsCommandStatusEnabled;
                    return;
                }
            }
        }


        /// <summary>Implements the Exec method of the IDTCommandTarget interface. This is called when the command is invoked.</summary>
        /// <param term='commandName'>The name of the command to execute.</param>
        /// <param term='executeOption'>Describes how the command should be run.</param>
        /// <param term='varIn'>Parameters passed from the caller to the command handler.</param>
        /// <param term='varOut'>Parameters passed from the command handler to the caller.</param>
        /// <param term='handled'>Informs the caller if the command was handled or not.</param>
        /// <seealso class='Exec' />
        public void Exec(string commandName, vsCommandExecOption executeOption, ref object varIn, ref object varOut, ref bool handled)
        {
            if(executeOption == vsCommandExecOption.vsCommandExecOptionDoDefault)
            {
                if (commandName == "ReplaceF1.Connect.ReplaceF1")
                {
                    // Get a reference to Solution Explorer.
                    Window activeWindow = _applicationObject.ActiveWindow;

                    ContextAttributes contextAttributes = activeWindow.DTE.ContextAttributes;
                    contextAttributes.Refresh();

                    List<string> attributes = new List<string>();
                    try
                    {
                        ContextAttributes highPri = contextAttributes == null ? null : contextAttributes.HighPriorityAttributes;
                        highPri.Refresh();
                        if (highPri != null)
                        {
                            foreach (ContextAttribute CA in highPri)
                            {
                                List<string> values = new List<string>();
                                foreach (string value in (ICollection)CA.Values)
                                {
                                    values.Add(value);
                                }
                                string attribute = CA.Name + "=" + String.Join(";", values.ToArray());
                                attributes.Add(CA.Name + "=");
                            }
                        }
                    }
                    catch (System.Runtime.InteropServices.COMException e)
                    {
                        // ignore this exception-- means there's no High Pri values here
                        string x = e.Message;
                    }
                    catch (System.Reflection.TargetInvocationException e)
                    {
                        // ignore this exception-- means there's no High Pri values here
                        string x = e.Message;
                    }
                    catch (System.Exception e)
                    {
                        System.Windows.Forms.MessageBox.Show(e.Message);
                        // ignore this exception-- means there's no High Pri values here
                        string x = e.Message;
                    }

                    // fetch context attributes that are not high-priority
                    foreach (ContextAttribute CA in contextAttributes)
                    {
                        List<string> values = new List<string>();
                        foreach (string value in (ICollection)CA.Values)
                        {
                            values.Add (value);
                        }
                        string attribute = CA.Name + "=" + String.Join(";", values.ToArray());
                        attributes.Add (attribute);
                    }

                    // Replace this call with whatever you want to do with the help context info 
                    HelpHandler.HandleF1 (attributes);
                }
            }
        }
        private DTE2 _applicationObject;
        private AddIn _addInInstance;
    }
}