SolutionOpenedAutoExp.cs

void SolutionOpened()
{
  string slnFile = mdte.Solution.FullName;
  string solutionDirectory = Path.GetDirectoryName(slnFile);
  string pathfileName = Path.GetFileNameWithoutExtension(slnFile) + ".autoexp";
  string patchFile = Path.Combine(solutionDirectory, pathfileName);
  
  if(File.Exists(patchFile))
  {
    string autoExpPatch = File.ReadAllText(patchFile);
    string autoExpPath = Environment.ExpandEnvironmentVariables("%VS100COMNTOOLS%\..\Packages\Debugger\autoexp.dat");
    string blockBegin = "; BEGIN AEP [AutoExpand] (" + pathfileName + ")";
    string blockEnd = "; END AEP [AutoExpand] (" + pathfileName + ")";
    
    // What follows is a bunch string parsing code that's not relevant to the article.
    // (1) We remove the previous auto expansion block we added, if we added one
    // in another session.
    // (2) We insert the new auto expansion patched section from our
    // SOLUTIONFILE_NAME.autoexp file.
    // (3) Save the new AutoExp.dat file.
  }
}