how to write the data in already opened text file

Koteswararao Mallisetti

16y3.7k.NET

i develop one windows service in the i use filesystemWatcher if any event is raised i write that information into text file in e:\ location all work fine but

while the service is running suppose i open that text file it shows the content but after at the stop that service an un handled exception thrown what is the problem

what i understand is when the file is open we try to write the content on that file through stream that error will come what is the solution for this problem

4 Replies

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Dorababu Meka16y ago
By using string builder you can do this..
A sample code

public bool saveBatchHeader(string m_strPath)
{
StringBuilder sb = new StringBuilder();
sb.AppendLine();
sb.Append(m_strRecordTypeCode.PadLeft(1, '0'));
sb.Append(m_strServiceClassCode.PadLeft(3, '0'));
sb.Append(m_strCompanyName.PadRight(16, ' '));
sb.Append(m_strCompanyDiscretionaryData.PadRight(20, ' '));
sb.Append(m_strCompanyIdentification.PadRight(10, ' '));
sb.Append(m_strStandardEntryClassCode.PadRight(3, ' '));
sb.Append(m_strCompanyEntryDescription.PadRight(10, ' '));
string m_strCompanyDescripDate = m_strCompanyDescriptiveDate.Replace("/", "");
sb.Append(m_strCompanyDescripDate.PadLeft(6, '0'));
string m_strEffDate = m_strEffectiveEntryDate.Replace("/", "");
sb.Append(m_strEffDate.PadLeft(6, '0'));
sb.Append(m_strJulianDate.PadRight(3, ' '));
sb.Append(m_strOriginatorStatusCode.PadRight(1, ' '));
sb.Append(m_strOriginationDFIIdentification.PadLeft(8, '0'));
sb.Append(m_strBatchNumber.PadLeft(7, '0'));
StreamWriter sw = File.AppendText(m_strPath);
sw.Write(sb);
sw.Close();
}
0
Suthish Nair16y ago
I think we can append an opened text file during runtime. Only a message will pop up asking "Do you want to reload the file.. yes/no.
here an example..
       using (FileStream fs = new FileStream(Server.MapPath("1.txt"), FileMode.Append, FileAccess.Write))
        {
            fs.Close();
            TextWriter tw = new StreamWriter(Server.MapPath("1.txt"), true);
            tw.WriteLine(System.Environment.NewLine + DateTime.Now);
            tw.Close();
        }

0
Sam Hobbs16y ago
Your service should open the output file in exclusive mode so that other applications cannot open the file whle the service is using it. You should also do as Maninder Wadhva says, or something similar.
0

Shankey16y ago

hi,

You cannot write to already open file. But you can change like if it is already open create copy of that file to another place and then edit content and once the file is not in use you can replace with your copy. Following is the code to identify whether the file is in use or not. Hope it will help you. But dont forget to mark my answer as accepted if it helped you :)

using System;
using System.IO;

namespace MyTestProject
{
    class Program
    {
        public static string __message;

        static void Main(string[] args)
        {
            string _path = "c:\\filewatcher.txt";
            bool retVal;
            retVal = FileInUse(_path);
            if (retVal)
                Console.WriteLine(__message);
            else
                Console.WriteLine("File not in use");
            
        }

        static bool FileInUse(string path)
        {
            try
            {
                //Just opening the file as open/create
                using (FileStream fs = new FileStream(path, FileMode.OpenOrCreate))
                {
                    //If required we can check for read/write by using fs.CanRead or fs.CanWrite
                }
                return false;
            }
            catch (IOException ex)
            {
                //check if message is for a File IO
                __message = ex.Message.ToString();
                if (__message.Contains("file is in use"))
                    return true;
                else
                    throw;
            }
        }
    }