/*
        獲取Oracle服務名
        1。查詢注冊表，獲取oracle安裝根目錄
            如：HKEY_LOCAL_MACHINE/SOFTWARE/ORACLE/ORACLE_HOME   REG_SZ  E:/ORACLE/ORA92
            得知oracle服務名文件所在地：根目錄/network/ADMIN/tnsnames.ora
           
        2。解析該文件，該文件結構如
            # ------------------------------------------------
            PORTAL =
            (DESCRipTION =
                (ADDRESS_LIST =
                (ADDRESS = (PROTOCOL = TCP)(HOST = 134.104.52.6)(PORT = 1521))
                )
                (CONNECT_DATA =
                (SERVICE_NAME = portal)
                )
            )

        3。解析要點：
            一行一行獲取再解析
            跳過以#打頭的注釋行
            過濾掉空格后，首字符在A~z之間的行就包含了Oracle服務名
            截取該行第一個“＝”號左邊的字符串，trim處理后就是Oracle服務名了
        */
        public static string[] GetOracleTnsNames()
        {
            try
            {
                // 查詢注冊表，獲取oracle服務文件路徑
                RegistryKey key = Registry.LocalMachine.OpenSubKey("SOFTWARE").OpenSubKey("ORACLE");
                string home = (string)key.GetValue("ORACLE_HOME");
                string file = home + @"/network/ADMIN/tnsnames.ora";

                // 解析文件
                string line;
                ArrayList arr = new ArrayList();
                StreamReader sr = new StreamReader(file);
                while ((line = sr.ReadLine()) != null)
                {
                    line = line.Trim();
                    if (line != "")
                    {
                        char c = line[0];
                        if ( c>= 'A' && c<='z')
                            arr.Add(line.Substring(0, line.IndexOf(' ')));
                    }
                }
                sr.Close();

                // 返回字符串數組
                return (string[])arr.ToArray(typeof(string));
            }
            catch (Exception ex)
            {
                return null;
            }
        }

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