VisualStudio.cs

using Microsoft.Win32;
using System;
using System.Collections.Generic;
using System.Collections;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;

namespace vscmd {
  public partial class VisualStudio : ComObject {
    #region Constructors

    private VisualStudio(object dte)
        : base(dte) { }

    const string ProgID = "VisualStudio.DTE";

    enum HResult : uint {
      MK_E_UNAVAILABLE = 0x800401E3, // Operation unavailable
    }

    public static VisualStudio GetOrCreate() {
      dynamic dte = GetActiveObjectOrDefault();
      if (dte != null)
        return new VisualStudio(dte);

      var type = Type.GetTypeFromProgID(ProgID);
      dte = Activator.CreateInstance(type);
      dte.UserControl = true;

      return new VisualStudio(dte);
    }

    static object GetActiveObjectOrDefault() {
      foreach (var progID in GetProgIDs()) {
        try {
          return Marshal.GetActiveObject(progID);
        } catch (COMException err) {
          if ((HResult)err.HResult != HResult.MK_E_UNAVAILABLE)
            throw;
        }
      }
      return null;
    }

    static IEnumerable<string> GetProgIDs() {
      yield return ProgID;

      const string prefix = ProgID + ".";
      var versioned = Registry.ClassesRoot.GetSubKeyNames()
          .Where(progID => progID.StartsWith(prefix))
          .OrderByDescending(progID => float.Parse(progID.Substring(prefix.Length)));
      foreach (var progID in versioned)
        yield return progID;
    }

    #endregion

    #region Window

    public void ActivateMainWindow() {
      this.Object.MainWindow.Activate();
    }

    #endregion

    #region ExecuteCommand

    public void OpenFile(FileInfo file) {
      this.Object.ExecuteCommand("File.OpenFile", "\"" + file.FullName + "\"");
    }

    #endregion

    #region Solution

    dynamic Solution {
      get { return this.Object.Solution; }
    }

    #endregion
  }
}