Remove all #region and #endregion lines from all *.cs files under a root folder

remove-regions.cs

void Main()
{
	// remove all occurances of #region and #endregion from CS files under a root folder
	
	var root = @"C:\Users\steve\Downloads\System_Windows_Forms_Calendar_003";
	
	var files = Directory.EnumerateFiles(root, "*.cs", SearchOption.AllDirectories);	
	if (files.Any())
	{
		var regex = new Regex(@"^\s*#(?:end)?region.*$");

		foreach (var path in files)
		{
			path.Dump();

			var lines = File.ReadAllLines(path);
			File.WriteAllLines(path, lines.Where(l => !regex.Match(l).Success));
		}
	}
}

This can pasted into LINQPad. Change the root variable to point to the folder containing source code. It will look for all *.cs files under that folder and remove all #region and #endregion lines from every file