使用C#程序处理PowerPoint文件中的字符串

最近， 有同事偶然发现Microsoft  Office PowerPoint可以被看作是一个压缩包，然后通过WinRAR解压出来一组XML文件。解压出来的文件包括：

一个索引文件名称为：[Content_Types].xml,

一个名为ppt的文件夹，在其内有两个重要的子文件夹：slides 和notesSlides

其中, [Content_Types].xml记录了每一张Slide的相对路径，每一个Slide note的相对路径。其内容如下图：

我们发现PPT中的所有内容都被记录在XML的<a:t></a:t>节点中， 所以，我们通过把所有a:t节点的内容导出，然后对内容进行修改，修改后再替换回原文件，这样将这一组文件进行压缩，生成了修改后的PowerPoint文件，该过程为PowerPoint的内容本地化提供了便捷途径。

这种做法相比较于调用Microsoft.Office.Interop.PowerPoint中的API的做法来说， 保留了原文的100%的格式，不需要后期PPT刷格式的操作。

以下是我们写的C#代码， 思路是将每张Slide的字符串导出到一个txt文件,通过trados翻译txt文件中的字符串，然后将修改后内容导入到PPT包内相应的XML文件中。

PPTZIPCommon

class PPTZIPCommon
    {
        /// <summary>
        /// read file [Content_Types].xml
        /// </summary>
        /// <param name="root"></param>
        /// <param name="SlideFiles">return slides </param>
        /// <param name="NotesFiles">return slide notes</param>
        internal static void ReadContentTypes(string root, ref List<string> SlideFiles, ref List<string> NotesFiles)
        {
            string ct_file = @"[Content_Types].xml";
            string ct_fullName = Path.Combine(root, ct_file);

            if (!File.Exists(ct_fullName))
            {
                MessageBox.Show(string.Format("the [Content_Types].xml not exist in {0}", root));
                return;
            }
            XmlDocument xml_doc = new XmlDocument();
            xml_doc.Load(ct_fullName);
            XmlElement rootElement = xml_doc.DocumentElement;
            string slide_types = "application/vnd.openxmlformats-officedocument.presentationml.slide+xml";
            string notes_types = "application/vnd.openxmlformats-officedocument.presentationml.notesSlide+xml";

            XmlNodeList nodes = rootElement.ChildNodes;
            foreach (XmlElement node in nodes)
            {
                if (node.Attributes["ContentType"].Value == slide_types)
                {
                    string relatedPath = node.Attributes["PartName"].Value.Remove(0, 1).Replace(@"/", @"\");
                    string file = Path.Combine(root, relatedPath);
                    SlideFiles.Add(file);
                }
                else if (node.Attributes["ContentType"].Value == notes_types)
                {
                    string relatedPath = node.Attributes["PartName"].Value.Remove(0, 1).Replace(@"/", @"\");
                    string file = Path.Combine(root, relatedPath);
                    NotesFiles.Add(file);
                }
            }
        }

        internal static string GetPPTNameFromFullPath(string scanFolder)
        {
            int lastIndexOfSlash = scanFolder.LastIndexOf(@"\");
            if (lastIndexOfSlash == scanFolder.Length - 1)
            {
                scanFolder = scanFolder.Remove(lastIndexOfSlash);
            }

            string lastString = scanFolder.Substring(scanFolder.LastIndexOf(@"\") + 1);
            string[] names = lastString.Split(new string[] { "." }, StringSplitOptions.RemoveEmptyEntries);
            return names[0];
        }
    }

PPTZIP

class PPTZIP
    {
        private static List<string> SlideFiles = new List<string>();
        private static List<string> NotesFiles = new List<string>();
             
        /// <summary>
        /// collect together all the <a:t>...</a:t> strings, put it in txt file
        /// txt file be saved to output\<original PPT name>_<fileName>.txt
        /// </summary>
        /// <param name="file">xml file that contains <a:t>...</a:t></param>
        /// <param name="output">the txt file be saved to the output folder</param>
        /// <param name="pptName">original PowerPoint file name</param>
        private static void ReadATContent2TXT(string file, string output, string pptName)
        {
            StringBuilder sb = new StringBuilder();
            using (StreamReader reader = new StreamReader(file))
            {
                string content = reader.ReadToEnd();
                string pattern = @"<a:t>.[^<>]+</a:t>";
                MatchCollection mc = Regex.Matches(content, pattern);

                for (int i = 0; i < mc.Count; i++)
                {
                    sb.AppendLine(string.Format("{0}^", mc[i].Value.Substring(5, mc[i].Value.LastIndexOf("<") - 5)));
                }
            }

            FileInfo fi = new FileInfo(file);
            string txtFile = Path.Combine(output, pptName+"_"+fi.Name + ".txt");
            using (StreamWriter writer = new StreamWriter(txtFile))
            {
                writer.Write(sb.ToString().Trim());
                writer.Flush();
                writer.Close();
            }
        }

        public static void Export2TXTs(string scanFolder)
        {
            string ppt_name = PPTZIPCommon.GetPPTNameFromFullPath(scanFolder);

            PPTZIPCommon.ReadContentTypes(scanFolder, ref SlideFiles, ref NotesFiles);

            if (null != SlideFiles && SlideFiles.Count > 0)
            {
                foreach (var file in SlideFiles)
                {
                    string outputfolder = Path.Combine(scanFolder, "SlideTXTs");
                    if (!Directory.Exists(outputfolder))
                        Directory.CreateDirectory(outputfolder);
                    string transFolder = Path.Combine(scanFolder, "SlideTXTs_Trans");
                    if (!Directory.Exists(transFolder))
                        Directory.CreateDirectory(transFolder);

                    ReadATContent2TXT(file, outputfolder, ppt_name);
                }
            }

            if (null != NotesFiles && NotesFiles.Count > 0)
            {
                foreach (var file in NotesFiles)
                {
                    string outputfolder = Path.Combine(scanFolder, "NotesTXTs");
                    if (!Directory.Exists(outputfolder))
                        Directory.CreateDirectory(outputfolder);
                    string transFolder = Path.Combine(scanFolder, "NotesTXTs_Trans");
                    if (!Directory.Exists(transFolder))
                        Directory.CreateDirectory(transFolder);

                    ReadATContent2TXT(file, outputfolder,ppt_name);
                }

            }
        }
    }

PPTZIPWriter

class PPTZIPWriter
    {
        private static List<string> SlideFiles = new List<string>();
        private static List<string> NotesFiles = new List<string>();              
         
        private static void Replace(string file, List<string> original, List<string> translated)
        {
            string content = string.Empty;
            using (StreamReader reader = new StreamReader(file))
            {
                content = reader.ReadToEnd();
                for (int i = 0; i < original.Count; i++)
                {
                    content = content.Replace(string.Format("<a:t>{0}</a:t>", original[i]), string.Format("<a:t>{0}</a:t>", translated[i]));
                }

                reader.Close();
            }

            using (StreamWriter writer = new StreamWriter(file))
            {
                writer.Write(content);
                writer.Flush();
                writer.Close();
            }

        }

        public static void Import2PPT(string scanFolder, string lan)
        {
            string ppt_name = PPTZIPCommon.GetPPTNameFromFullPath(scanFolder);

            // fullfill the two lists: SlideFiles and NotesFiles
            PPTZIPCommon.ReadContentTypes(scanFolder,ref SlideFiles, ref NotesFiles);

            string srcFolder = "SlideTXTs";
            string trgFolder = "SlideTXTs_Trans";

            string srcFullPath = Path.Combine(scanFolder, srcFolder);
            string trgFullPath = Path.Combine(scanFolder, trgFolder);
            foreach (var file in SlideFiles)
            {
                ReplaceATContent(file, srcFullPath, trgFullPath, ppt_name, lan);
            }

            string srcFolderNotes = "NotesTXTs";
            string trgFolderNotes = "NotesTXTs_Trans";
            string srcFullPath_trans = Path.Combine(scanFolder, srcFolderNotes);
            string trgFullPath_trans = Path.Combine(scanFolder, trgFolderNotes);
            foreach (var file in NotesFiles)
            {
                ReplaceATContent(file, srcFullPath_trans, trgFullPath_trans, ppt_name, lan);
            }
        }

        private static void ReplaceATContent(string file, string srcFolder, string trgFolder, string pptName, string lan)
        {
            if (!(Directory.Exists(srcFolder) && Directory.Exists(trgFolder)))
            {
                MessageBox.Show("SlideTXTs/NotesTXTs or SlideTXTs_Trans/NotesTXTs_Trans not exist");
                return;
            }

            FileInfo fi = new FileInfo(file);
            string srcFileName = string.Format("{0}_{1}.txt",pptName,fi.Name);
            string srcFileFullPath = Path.Combine(srcFolder, srcFileName);

             string trgFileName= string.Empty;
            if(lan==string.Empty)
                trgFileName = string.Format("{0}_{1}.txt", pptName, fi.Name);
            else
                trgFileName = string.Format("{0}_{1}_{2}.txt",pptName, fi.Name,lan);
            string trgFileFullPath = Path.Combine(trgFolder, trgFileName);

            if (!(File.Exists(srcFileFullPath) && File.Exists(trgFileFullPath)))
            {
                MessageBox.Show(string.Format(@"File {0} not replaced",file));
                return;
            }

            List<string> originalString = new List<string>();
            using (StreamReader reader = new StreamReader(srcFileFullPath))
            {
                string content = reader.ReadToEnd().Trim();
                string[] strings = content.Split(new string[] { "^" }, StringSplitOptions.RemoveEmptyEntries);
                for (int i = 0; i < strings.Length; i++)
                {
                    originalString.Add(strings[i].Contains("\r\n") ? strings[i].Remove(0, 2) : strings[i]);
                }
            }

            List<string> translatedString = new List<string>();
            using (StreamReader reader = new StreamReader(trgFileFullPath))
            {
                string content = reader.ReadToEnd().Trim();
                string[] strings = content.Split(new string[] { "^" }, StringSplitOptions.RemoveEmptyEntries);
                for (int i = 0; i < strings.Length; i++)
                {
                    translatedString.Add(strings[i].Contains("\r\n") ? strings[i].Remove(0, 2) : strings[i]);
                }
            }

            if (originalString.Count != translatedString.Count)
            {
                MessageBox.Show(string.Format(@"translation string count not match:{0}",file));
                return;
            }

            Replace(file, originalString, translatedString);
        }        
    }