ソース整形

using System;
using System.IO;
using EnvDTE; //Add Reference to EnvDTE,EnvDTE80

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            EnvDTE.Solution soln = System.Activator.CreateInstance(
                Type.GetTypeFromProgID("VisualStudio.Solution.14.0")) as EnvDTE.Solution;
            soln.DTE.MainWindow.Visible = true;
            FormatFile(@"C:\test\src.cs", soln);
            //Set ProgID of your VS
            //Visual Studio 2008 -> 10.0
            //Visual Studio 2010 -> 11.0
            //Visual Studio 2013 -> 12.0
            //Visual Studio 2015 -> 14.0
            //var files = Directory.GetFiles(@"C:\test", "*src.cs", SearchOption.AllDirectories).ToList();
            //files.ForEach(file => {
            //    FormatFile(file, soln);
            //    Console.WriteLine($"format {file}"); //C#6.0
            //});
        }

        static void FormatFile(string file, EnvDTE.Solution soln)
        {
            soln.DTE.ItemOperations.OpenFile(file);
            TextSelection selection = soln.DTE.ActiveDocument.Selection as TextSelection;
            selection.SelectAll();
            selection.SmartFormat();
            soln.DTE.ActiveDocument.Save();
            soln.DTE.ActiveWindow.Close();
        }
    }
}