Create Folder and Subfolder at Run Time

Create Instance of DirectoryInfo To Create Directories.
Pass the Page object so that we can the the serverpath
Directory.CreateDirectory({path}) is Used to create Parent Directory.

and Further we can use :
childDir =parentDir.CreateSubdirectory("Child");
to create child Directory inside the Parent Folder

public static void FolderCreation(Page page)
{
      //variable declaration
      string serverPath = null;
      string virtualServerPath = null;
      DirectoryInfo parentDir = null;
      DirectoryInfo childDir = null;
      try
       {
           //getting full server path
           serverPath = page.Server.MapPath(".");
          //server path -1 step
          virtualServerPath = serverPath.Substring(0, serverPath.LastIndexOf("\\"));
          virtualServerPath = virtualServerPath + @"\MyFolder\Parent";

          //create the directory with the name Parent in MyFolder
           parentDir = Directory.CreateDirectory(virtualServerPath);
          
	//Create Child Directory inside Parent folder
         childDir =parentDir.CreateSubdirectory("Child");
       }
      catch{}
}