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Here is the setup. On error i want to write (append) the error message to an SPFile in a document library. If the file doesn't already exist i want to create it. Searching around this is what i came up with. However, when it attempts to create the file using SPFolder.Files.Add it throws an I/O Error exception (no inner exception/better description during debug). If the file is already there, however, all is well and the file is updated as expected. So first question would be what am i doing wrong. Second would be is there a better way to do what i am doing (no doubt there is).....any help appreciated

System.Text.ASCIIEncoding enc = new System.Text.ASCIIEncoding();
UnicodeEncoding uniEncoding = new UnicodeEncoding();
StringBuilder errors = new StringBuilder();

foreach (Exception e in cc.aggregatedException.m_InnerExceptionsList)
    errors.Append(e.Message + Environment.NewLine);

SPFile logFile = csvList.Items.Cast<SPListItem>()
                              .Where(x => x.Name.Equals(logFileName))
                              .Select(x => x.File)

if (logFile == null)
    using (MemoryStream ms = new MemoryStream())
         using (StreamWriter sw = new StreamWriter(ms, uniEncoding))

         SPFolder csvLibraryFolder = SPContext.Current.Web.Folders[libraryName];
         csvLibraryFolder.Files.Add(logFileName, ms, false);
    byte[] fileContents = logFile.OpenBinary();
    string newContents = enc.GetString(fileContents) + 
                             Environment.NewLine + errors.ToString();
share|improve this question
Can't say that I see any errors. Not that often I add files with MemoryStream, but I have always added them like this: folder.Files.Add(fileName, memoryStream.ToArray(), bool); – Anders Aune Oct 27 '12 at 11:12
That fixed it....if you want add this as an answer and i'll give you the credit. Can anyone tell me why passing a byte[] vs just the memorystream to the Add method causes an I/O Exception? Many many thanks!!!! – MikeC Oct 29 '12 at 15:52
up vote 2 down vote accepted

Add the MemoryStream as a byte[]:

folder.Files.Add(fileName, memoryStream.ToArray(), bool);
share|improve this answer

This is a simple approach I have used in the past with a try/catch so maybe you could revamp for your needs:

string myResponse = "whatever needs to be written to the file...";
        string filename = "C:\\splogs\\" + (DateTime.Now).ToString("yyyyMMdd") + "_customlog.log";
        FileStream logStream = new FileStream(@filename, FileMode.Append);
        StreamWriter logfile = new StreamWriter(logStream);
share|improve this answer
A good approach to log to a file in the file system. +1 :) I would prefer to log to a file in the actual document library because otherwise nobody will ever pay attention to it (or more importantly have the access to pay attention to it :) – MikeC Oct 29 '12 at 15:44

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