Разработка расширений для Visual Studio на C#

using Microsoft.VisualStudio.Shell;
using System;
using System.Runtime.InteropServices;
using System.Threading;
using System.Threading.Tasks;

namespace MyFirstExtension
{
    [PackageRegistration(UseManagedResourcesOnly = true, AllowsBackgroundLoading = true)]
    [InstalledProductRegistration("#110", "#112", "1.0", IconResourceID = 400)]
    [Guid("Your-GUID-Here")]
    [ProvideMenuResource("Menus.ctmenu", 1)]
    public sealed class MyFirstExtensionPackage : AsyncPackage
    {
        protected override async Task InitializeAsync(CancellationToken cancellationToken, IProgress<ServiceProgressData> progress)
        {
            await base.InitializeAsync(cancellationToken, progress);
            await JoinableTaskFactory.SwitchToMainThreadAsync(cancellationToken);
            var commandService = this.GetService(typeof(IMenuCommandService)) as OleMenuCommandService;
            if (commandService != null)
            {
                var menuCommandID = new CommandID(new Guid("Your-GUID-Here"), 0x100);
                var menuItem = new MenuCommand(MenuItemCallback, menuCommandID);
                commandService.AddCommand(menuItem);
            }
        }

        private void MenuItemCallback(object sender, EventArgs e)
        {
            // Ваша логика пользовательской команды здесь
            System.Windows.MessageBox.Show("Привет из MyFirstExtension!");
        }
    }
}

<CommandTable xmlns="http://schemas.microsoft.com/VisualStudio/2005-10-18/CommandTable" xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <Commands>
    <Menu guid="guidMyFirstExtensionCmdSet" id="MyMenuGroup" priority="0x0600" type="Menu">
      <Parent guid="guidSHLMainMenu" id="IDG_VS_MM_TOOLSADDINS1"/>
      <Strings>
        <ButtonText>Мое первое расширение</ButtonText>
        <CommandName>MyFirstExtension</CommandName>
      </Strings>
    </Menu>
  </Commands>
  <Buttons>
    <Button guid="guidMyFirstExtensionCmdSet" id="MyCommand" priority="0x0100" type="Button">
      <Parent guid="guidMyFirstExtensionCmdSet" id="MyMenuGroup" />
      <Icon guid="guidImages" id="bmpPic1" />
      <Strings>
        <ButtonText>Моя команда</ButtonText>
      </Strings>
    </Button>
  </Buttons>
  <Bitmaps>
    <Bitmap guid="guidImages" href="Resources\MyIcon.png" usedList="bmpPic1, bmpPic2, bmpPicSearch, bmpPicX, bmpPicArrows, bmpPicStrikethrough"/>
  </Bitmaps>
</CommandTable>

[ProvideToolWindow(typeof(MyToolWindow), Style = VsDockStyle.Tabbed, Orientation = ToolWindowOrientation.Right)]
public sealed class MyFirstExtensionPackage : AsyncPackage
{
    protected override async Task InitializeAsync(CancellationToken cancellationToken, IProgress<ServiceProgressData> progress)
    {
        await base.InitializeAsync(cancellationToken, progress);
        await JoinableTaskFactory.SwitchToMainThreadAsync(cancellationToken);
        var toolWindow = this.FindToolWindow(typeof(MyToolWindow), 0, true);
        if (toolWindow != null)
        {
            var window = (MyToolWindow)toolWindow;
            window.Frame.Caption = "Мое пользовательское окно инструментов";
            window.Visible = true;
        }
    }
}

public class MyToolWindow : ToolWindowPane
{
    public MyToolWindow() : base(null)
    {
        this.Caption = "Мое пользовательское окно инструментов";
        this.Content = new MyToolWindowControl();
    }
}

public class MyToolWindowControl : UserControl
{
    public MyToolWindowControl()
    {
        this.Content = new TextBlock { Text = "Привет из моего пользовательского окна инструментов!" };
    }
}

[ProvideLanguageService(typeof(MyLanguageService), "MyLanguage", 100)]
public sealed class MyFirstExtensionPackage : AsyncPackage
{
    protected override async Task InitializeAsync(CancellationToken cancellationToken, IProgress<ServiceProgressData> progress)
    {
        await base.InitializeAsync(cancellationToken, progress);
        await JoinableTaskFactory.SwitchToMainThreadAsync(cancellationToken);
        // Инициализируйте вашу языковую службу здесь
    }
}

public class MyLanguageService : ILanguageService
{
    public void InitializeService(IServiceProvider serviceProvider, ITextBuffer textBuffer)
    {
        // Инициализируйте вашу языковую службу здесь
    }

    public void ShutdownService(IServiceProvider serviceProvider, ITextBuffer textBuffer)
    {
        // Завершите вашу языковую службу здесь
    }
}