C# - Changes the extension of a file

gistfile1.cs

        /// <summary>
        /// Changes the file extension by moving it.
        /// </summary>
        /// <param name="filePath">Full path to the file for which change the extension.</param>
        /// <param name="extension">The new file extension.</param>
        /// <returns>The path to the file, with the new extension.</returns>
        private string ChangeFileExtension(string filePath, string extension)
        {
            if (!extension.StartsWith("."))
                extension = "." + extension;

            var d = Path.GetDirectoryName(filePath);
            var fn = Path.GetFileNameWithoutExtension(filePath);
            var newFp = Path.Combine(d, fn + extension);

            File.Move(filePath, newFp);

            return newFp;
        }