删除文本文件指定行

/// <summary>
        /// 删除文本文件指定行
        /// </summary>
        /// <param name="deleteLineIndex"></param>
        private void DeleteLine(int deleteLineIndex)
        {
            StreamReader reader = new StreamReader(PathFile);

            string text = reader.ReadToEnd();

            reader.Close();

            string[] textlines = Regex.Split(text, Environment.NewLine);
            StringBuilder str = new StringBuilder();
            for (int i = 0; i < textlines.Length; i++)
            {
                if (i == deleteLineIndex)
                    continue;
                str.AppendLine(textlines[i]);
            }
         
            StreamWriter writer = new StreamWriter(PathFile);
            writer.Write(str.ToString());
            writer.Close();
        }