"is in use by other process"? - winforms

Question

I have a log file for my application and the log file has maximum of 10 log files
that can be created. The code snippet is as follows,
Stream logFileStream = null;
string file = Config.LOG_FILE;
m_strLogfile = Config.LOG_FILE + Config.LOG_FILE_EXT;
while (File.Exists(m_strGeneralFilePath + file + Config.LOG_FILE_EXT))
{
logFileStream = File.OpenRead(m_strGeneralFilePath + file + Config.LOG_FILE_EXT);
// if(!logFileStream.Length.Equals(logSize))
if ( logFileStream.Length > Convert.ToInt32(logSize)) // approx. 1MB 1.000.000
{
for (int i = 9; i > 0; i--)
{
if (i == 9)
{
if (File.Exists(Config.LOG_FILE + i + Config.LOG_FILE_EXT))
{
File.Delete(Config.LOG_FILE + i + Config.LOG_FILE_EXT);
}
}
if (File.Exists(m_strGeneralFilePath + Config.LOG_FILE + i + Config.LOG_FILE_EXT))
{
System.IO.File.Move(m_strGeneralFilePath + Config.LOG_FILE + i + Config.LOG_FILE_EXT, m_strGeneralFilePath + Config.LOG_FILE + (i + 1) + Config.LOG_FILE_EXT);
}
}
System.IO.File.Move(m_strGeneralFilePath + Config.LOG_FILE + Config.LOG_FILE_EXT, m_strGeneralFilePath + Config.LOG_FILE + "1" + Config.LOG_FILE_EXT);
File.Create(m_strGeneralFilePath + Config.LOG_FILE + Config.LOG_FILE_EXT);
}
}
if (logFileStream != null)
{
logFileStream.Close();
logFileStream.Dispose();
}
As soon as it comes to System.IO.File.Move(m_strGeneralFilePath + Config.LOG_FILE + Config.LOG_FILE_EXT, m_strGeneralFilePath + Config.LOG_FILE + "1" + Config.LOG_FILE_EXT); it hits an exception saying "it is used by some other process", how can I get rid of this?
Please help me in this.
Thanks in advance.
I am using .net 4.0 c# winforms.

Answer 1

The exception is thrown because you are trying to move a file which is already opened for reading in the stream object "logFileStream". So what you need to do is close this file stream just before you start moving it rather than in the end.
Your code should be some what like this, please note the close and dispose statements I provided just before your move statement.
Stream logFileStream = null;
string file = Config.LOG_FILE;
m_strLogfile = Config.LOG_FILE + Config.LOG_FILE_EXT;
while (File.Exists(m_strGeneralFilePath + file + Config.LOG_FILE_EXT))
{
logFileStream = File.OpenRead(m_strGeneralFilePath + file + Config.LOG_FILE_EXT);
// if(!logFileStream.Length.Equals(logSize))
if ( logFileStream.Length > Convert.ToInt32(logSize)) // approx. 1MB 1.000.000
{
// this is where you should close the file stream, assuming that you are not using the stream anymore.
logFileStream.Close();
logFileStream.Dispose();
for (int i = 9; i > 0; i--)
{
if (i == 9)
{
if (File.Exists(Config.LOG_FILE + i + Config.LOG_FILE_EXT))
{
File.Delete(Config.LOG_FILE + i + Config.LOG_FILE_EXT);
}
}
if (File.Exists(m_strGeneralFilePath + Config.LOG_FILE + i + Config.LOG_FILE_EXT))
{
System.IO.File.Move(m_strGeneralFilePath + Config.LOG_FILE + i + Config.LOG_FILE_EXT, m_strGeneralFilePath + Config.LOG_FILE + (i + 1) + Config.LOG_FILE_EXT);
}
}
System.IO.File.Move(m_strGeneralFilePath + Config.LOG_FILE + Config.LOG_FILE_EXT, m_strGeneralFilePath + Config.LOG_FILE + "1" + Config.LOG_FILE_EXT);
File.Create(m_strGeneralFilePath + Config.LOG_FILE + Config.LOG_FILE_EXT);
}
}

Answer 2

the FileStream was not closed after, so the change was,
I just changed the line
File.Create(m_strGeneralFilePath + Config.LOG_FILE + Config.LOG_FILE_EXT); to using block for more convenience.
using (FileStream fs = File.Create(m_strGeneralFilePath + Config.LOG_FILE + Config.LOG_FILE_EXT))
{
fs.Flush();
fs.Close();
}