Windows读写INI文件注意事项

GetPrivateProfileString最长读取65535个字符；
如果ini文件的Value值超过65535，GetPrivateProfileString读取会发生一些无法预料的错误；

WritePrivateProfileString理论上最长写入65535个字符，实际这个写入长度限制会有波动，尚不确定原因，建议不要太长；
1、调用WritePrivateProfileString写入超过65535长度，GetPrivateProfileString读取失败且不会返回默认值；
2、调用WritePrivateProfileString写入超过65535长度后手动修改ini文件，GetPrivateProfileString读取会发生一些无法预料的错误；

补充一：

写入65535个字符，GetPrivateProfileString成功读取65535个字符，返回值为65535；

写入65536个字符，GetPrivateProfileString读取失败，返回值为0；

写入65537个字符，GetPrivateProfileString读取失败，返回值为1；

扩展:

 public class IniParser
    {
        private Hashtable keyPairs = new Hashtable();
        private String iniFilePath;
        private struct SectionPair
        {
            public String Section;
            public String Key;
        }
        /// <summary>
        /// Opens the INI file at the given path and enumerates the values in the IniParser.
        /// </summary>
        /// <param name="iniPath">Full path to INI file.</param>
        public IniParser(String iniPath)
        {
            TextReader iniFile = null;
            String strLine = null;
            String currentRoot = null;
            String[] keyPair = null;
            iniFilePath = iniPath;
            if (File.Exists(iniPath))
            {
                try
                {
  
                    iniFile = new StreamReader(iniPath, Encoding.GetEncoding("GB2312"));
                    strLine = iniFile.ReadLine();
                    while (strLine != null)
                    {
                        strLine = strLine.Trim();
                            //.ToUpper();
                        if (strLine != "")
                        {
                            if (strLine.StartsWith("[") && strLine.EndsWith("]"))
                            {
                                currentRoot = strLine.Substring(1, strLine.Length - 2);
                            }
                            else
                            {
                                keyPair = strLine.Split(new char[] { '=' }, 2);
                                SectionPair sectionPair;
                                String value = null;
                                if (currentRoot == null)
                                    currentRoot = "ROOT";
                                sectionPair.Section = currentRoot;
                                sectionPair.Key = keyPair[0];
                                if (keyPair.Length > 1)
                                    value = keyPair[1];
                                keyPairs.Add(sectionPair, value);
                            }
                        }
                        strLine = iniFile.ReadLine();
                    }
                }
                catch (Exception ex)
                {
                    throw ex;
                }
                finally
                {
                    if (iniFile != null)
                        iniFile.Close();
                }
            }
            else
                throw new FileNotFoundException("Unable to locate " + iniPath);
        }
        /// <summary>
        /// Returns the value for the given section, key pair.
        /// </summary>
        /// <param name="sectionName">Section name.</param>
        /// <param name="settingName">Key name.</param>
        public String GetSetting(String sectionName, String settingName)
        {
            SectionPair sectionPair;
            sectionPair.Section = sectionName;
            //.ToUpper();
            sectionPair.Key = settingName;
            //.ToUpper();
            var str = ((String)keyPairs[sectionPair]);
            return str!=null&&str.StartsWith("\"")?str.Substring(1,str.Length-2):str;
        }
        /// <summary>
        /// Enumerates all lines for given section.
        /// </summary>
        /// <param name="sectionName">Section to enum.</param>
        public String[] EnumSection(String sectionName)
        {
            ArrayList tmpArray = new ArrayList();
            foreach (SectionPair pair in keyPairs.Keys)
            {
                if (pair.Section == sectionName)
                    //.ToUpper())
                    tmpArray.Add(pair.Key);
            }
            return (String[])tmpArray.ToArray(typeof(String));
        }
        /// <summary>
        /// Adds or replaces a setting to the table to be saved.
        /// </summary>
        /// <param name="sectionName">Section to add under.</param>
        /// <param name="settingName">Key name to add.</param>
        /// <param name="settingValue">Value of key.</param>
        public void AddSetting(String sectionName, String settingName, String settingValue)
        {
            SectionPair sectionPair;
            sectionPair.Section = sectionName;
            //.ToUpper();
            sectionPair.Key = settingName;
            //.ToUpper();
            if (keyPairs.ContainsKey(sectionPair))
                keyPairs.Remove(sectionPair);
            keyPairs.Add(sectionPair, settingValue);
        }
        /// <summary>
        /// Adds or replaces a setting to the table to be saved with a null value.
        /// </summary>
        /// <param name="sectionName">Section to add under.</param>
        /// <param name="settingName">Key name to add.</param>
        public void AddSetting(String sectionName, String settingName)
        {
            AddSetting(sectionName, settingName, null);
        }
        /// <summary>
        /// Remove a setting.
        /// </summary>
        /// <param name="sectionName">Section to add under.</param>
        /// <param name="settingName">Key name to add.</param>
        public void DeleteSetting(String sectionName, String settingName)
        {
            SectionPair sectionPair;
            sectionPair.Section = sectionName;//.ToUpper();
            sectionPair.Key = settingName;//.ToUpper();
            if (keyPairs.ContainsKey(sectionPair))
                keyPairs.Remove(sectionPair);
        }
        /// <summary>
        /// Save settings to new file.
        /// </summary>
        /// <param name="newFilePath">New file path.</param>
        public void SaveSettings(String newFilePath)
        {
            ArrayList sections = new ArrayList();
            String tmpValue = "";
            String strToSave = "";
            foreach (SectionPair sectionPair in keyPairs.Keys)
            {
                if (!sections.Contains(sectionPair.Section))
                    sections.Add(sectionPair.Section);
            }
            foreach (String section in sections)
            {
                strToSave += ("[" + section + "]\r\n");
                foreach (SectionPair sectionPair in keyPairs.Keys)
                {
                    if (sectionPair.Section == section)
                    {
                        tmpValue = (String)keyPairs[sectionPair];
                        if (tmpValue != null)
                            tmpValue = "=" + tmpValue;
                        strToSave += (sectionPair.Key + tmpValue + "\r\n");
                    }
                }
                strToSave += "\r\n";
            }
            try
            {
                FileStream fs=new FileStream(newFilePath, FileMode.Create);
                TextWriter tw = new StreamWriter(fs,Encoding.GetEncoding("GB2312"));
                tw.Write(strToSave);
                tw.Close();
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }
        /// <summary>
        /// Save settings back to ini file.
        /// </summary>
        public void SaveSettings()
        {
            SaveSettings(iniFilePath);
        }
    }