I created a Solution project.

This solution have two SolutionFolders.

SolutionFolder' s each name is "Service","Main"
and they have own aproject

i added a project in a solutionFolder,it's name "service".

but aerror occured.

errormessage 'duplicated solutionfolder'

my recipe action is like this

EnvDTE.DTE dte = this.GetService<EnvDTE.DTE>(true);

Solution2 soln = (Solution2)dte.Solution;

Project prj;
SolutionFolder SF ;

prj = soln.AddSolutionFolder("Service"); // error duplicatedsolutionfolder

SF = (SolutionFolder)prj.Object;


SF.AddFromTemplate(templateFile, destination, strProjectName);

EnvDTE.DTE dte = this.GetService<EnvDTE.DTE>(true);

Solution2 soln = (Solution2)dte.Solution;

SolutionFoldersf ;

foreach (Project proj in soln.Projects)
{
System.Windows.Forms.MessageBox.Show(proj.Kind, " proj.Kind ");

System.Windows.Forms.MessageBox.Show(proj.Name, " proj.Name ");

if (proj.Kind == ProjectKinds.vsProjectKindSolutionFolder && proj.Name == "Service" )
{

sf = (SolutionFolder)proj.Object;
sf .AddFromTemplate(templateFile, destination, strProjectName);
break;
}
}

EnvDTE.DTE dte = this.GetService<EnvDTE.DTE>(true);

Solution2 soln = (Solution2)dte.Solution;

SolutionFoldersf ;

foreach (Project proj in soln.Projects)
{
System.Windows.Forms.MessageBox.Show(proj.Kind, " proj.Kind ");

System.Windows.Forms.MessageBox.Show(proj.Name, " proj.Name ");

if (proj.Kind == ProjectKinds.vsProjectKindSolutionFolder && proj.Name == "Service" )
{

sf = (SolutionFolder)proj.Object;
sf .AddFromTemplate(templateFile, destination, strProjectName);
break;
}
}