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c# Two FileStreams write to text file but just one affect file

below code:
var fs = new FileStream(#"C:\Users\Michał\Desktop\tools\test.txt",
FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite);
var fs2 = new FileStream(#"C:\Users\Michał\Desktop\tools\test.txt",
FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite);
int a = 0;
while (a < 3)
{
byte[] info = new UTF8Encoding(true).GetBytes("DEF_");
byte[] info2 = new UTF8Encoding(true).GetBytes("abc_");
fs.Write(info, 0, info.Length);
Thread.Sleep(100);
fs2.Write(info2, 0, info2.Length);
Thread.Sleep(1000);
++a;
}
fs.Close();
fs2.Close();
Why result is that in a file there is just "abc_abc_abc" ?
FileShare.ReadWrite means for me other processes/threads can write to this file in the same time in FileStream ctor call.

You can achieve the desired behavior as follows:
using (var fs = new FileStream("test.txt", FileMode.Create, FileAccess.ReadWrite, FileShare.ReadWrite))
using (var fs2 = new FileStream("test.txt", FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite))
{
byte[] info = new UTF8Encoding(true).GetBytes("DEF_");
byte[] info2 = new UTF8Encoding(true).GetBytes("abc_");
for (int i = 0; i < 3; i++)
{
fs.Seek(0, SeekOrigin.End);
fs.Write(info, 0, info.Length);
fs.Flush();
fs2.Seek(0, SeekOrigin.End);
fs2.Write(info2, 0, info2.Length);
fs2.Flush();
}
}
Before writing, each pointer of stream must be positioned at the end. This is done using the Seek method.
After writing, you need to flush the buffer to disk. This ensures that the stream is in the correct state before starting the next write. To do this, use the Flush method.
When you create a stream in its constructor, you can specify the FileOptions.WriteThrough. According to its description, the intermediate buffer should not be used. However, it still doesn't work without the Flush method. Perhaps experts will explain the reason.

Read and overwrite at the same FileStream

I'm using a FileStream to lock the File to be not writeable for other processes and also read and write to it, I'm using following method for it:
public static void ChangeOrAddLine(string newLine, string oldLine = "")
{
string filePath = "C:\\test.txt";
FileMode fm = FileMode.Create;
//FileMode fm = FileMode.OpenOrCreate;
using (FileStream fs = new FileStream(filePath, FileMode.Create, FileAccess.ReadWrite, FileShare.Read))
using (StreamReader sr = new StreamReader(fs))
using (StreamWriter sw = new StreamWriter(fs))
{
List<string> lines = sr.ReadToEnd().Split(new string[] { "\r\n" }, StringSplitOptions.None).ToList();
bool lineFound = false;
if (oldLine != "")
for (int i = 0; i < lines.Count; i++)
if (lines[i] == oldLine)
{
lines[i] = newLine;
lineFound = true;
break;
}
if (!lineFound)
lines.Add(newLine);
sw.Write(string.Join("\r\n", lines));
}
}
I want to overwrite it with the new content but i don't find the right FileMode, using FileMode.OpenOrCreate just appends the new content to the old and FileMode.Create deletes the file-content at the time, the FileStream fm has been initialized, so the file is empty.
I need to just clear the old content at the moment, when i write the new content to it without losing the write-lock on it during the method is running.

OpenOrCreate just appends ...
Because you don't reposition after the reading.
That also shows the main problem with your approach: The FileStream only has one Position, and the Reader and the Writer heavily use caching.
However, as long as you want to replace everything and really need that locking scheme:
using (FileStream fs = new FileStream(filePath,
FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.Read))
{
using (StreamReader sr = new StreamReader(fs))
{
... // all the reading
}
fs.Position = 0;
using (StreamWriter sw = new StreamWriter(fs))
{
sw.Write(string.Join("\r\n", lines));
}
fs.SetLength(fs.Position); // untested, something along this line
}
and maybe you have to convince the sw and sr to leave their stream open.
But I have to note that the FileShare.Read flag doesn't make too much sense in this scenario. A reader could see al sorts of inconsistent data, including torn lines and broken UTF8 characters.

How to use filestream for copying files in c#

I want to copy a file from one folder to another folder using filestream.How this can be achived.when I try to use file.copy I was getting this file is using by another process, to avoid this I want to use file stream using c#. Can some one provide a sample for copying a file from one folder to another.

for copying i used below code :-
public static void Copy(string inputFilePath, string outputFilePath)
{
int bufferSize = 1024 * 1024;
using (FileStream fileStream = new FileStream(outputFilePath, FileMode.OpenOrCreate, FileAccess.Write,FileShare.ReadWrite))
//using (FileStream fs = File.Open(<file-path>, FileMode.Open, FileAccess.Read, FileShare.Read))
{
FileStream fs = new FileStream(inputFilePath, FileMode.Open, FileAccess.ReadWrite);
fileStream.SetLength(fs.Length);
int bytesRead = -1;
byte[] bytes = new byte[bufferSize];
while ((bytesRead = fs.Read(bytes, 0, bufferSize)) > 0)
{
fileStream.Write(bytes, 0, bytesRead);
}
}
}

You can use Stream.CopyTo method to copy the file like below:
public static string CopyFileStream(string outputDirectory, string inputFilePath)
{
FileInfo inputFile = new FileInfo(inputFilePath);
using (FileStream originalFileStream = inputFile.OpenRead())
{
var fileName = Path.GetFileName(inputFile.FullName);
var outputFileName = Path.Combine(outputDirectory, fileName);
using (FileStream outputFileStream = File.Create(outputFileName))
{
originalFileStream.CopyTo(outputFileStream);
}
return outputFileName;
}
}

string fileName = "Mytest.txt";
string sourcePath = #"C:\MyTestPath";
string targetPath = #"C:\MyTestTarget";
string sourceFile = System.IO.Path.Combine(sourcePath, fileName);
string destFile = System.IO.Path.Combine(targetPath, fileName);
{
System.IO.Directory.CreateDirectory(targetPath);
}
// To copy a file to another location and
// overwrite the destination file if it already exists.
System.IO.File.Copy(sourceFile, destFile, true);

Convert ushort image to binary?

I have an image in ushort variable, want to save this image in binary format.
Please, anyone, tell me How can this be done using C#?
I have tried this but its not working
ushort[] Depthdata;
Depthdata = new ushort[DWidth * DHeight];
string s1 = string.Format("{0}", count_depth);
FileStream fs = new FileStream("C:\\img" + s1 + ".bin", FileMode.Create, FileAccess.Write);
BinaryWriter bw = new BinaryWriter(fs);
string image_str = Convert.ToString(Imagedata);
bw.Write(image_str);
bw.Close();
fs.Close();
Here is attached my full code

I would like to mention that the code here, and the one in your link are different...
In any case, going by the one in your link:
ushort[] Depthdata;
....
string s1 = string.Format("{0}", count_depth);
FileStream fs = new FileStream("G:\\test" + s1 + ".bin", FileMode.Create, FileAccess.Write);
BinaryWriter bw = new BinaryWriter(fs);
string depth_str = Convert.ToString(Depthdata);
bw.Write(depth_str);
bw.Close();
fs.Close();
You shouldn't actually need to convert your Depthdata to a string. BinaryWriter can actually take a ushort value in one of its overloads. Why not just iterate through and write it out? Also, you should use using statements for your filestream and binarywriter.
Try the following:
using(FileStream fs = new FileStream("G:\\test" + s1 + ".bin", FileMode.Create, FileAccess.Write))
{
using(BinaryWriter bw = new BinaryWriter(fs))
{
foreach(ushort value in Depthdata)
{
bw.write(value);
}
}
}

I think this will help you.i tested this on *.tiff file
first make separate Class Ext
public static class Ext
{
public static string ToHexString(this byte[] hex)
{
if (hex == null) return null;
if (hex.Length == 0) return string.Empty;
var s = new StringBuilder();
foreach (byte b in hex)
{
s.Append(b.ToString("x2"));
}
return s.ToString().ToUpper();
}
}
then you can Add following code to convert image to string binary
FileStream fs=new FileStream(ImgPathID, FileMode.Open, FileAccess.Read); //set file stream
Byte[] bindata=new byte[Convert.ToInt32(fs.Length)];
fs.Read(bindata, 0, Convert.ToInt32(fs.Length));
string bindatastring = Ext.ToHexString(bindata);// call to class

How can I read a text file without locking it?

I have a windows service writes its log in a text file in a simple format.
Now, I'm going to create a small application to read the service's log and shows both the existing log and the added one as live view.
The problem is that the service locks the text file for adding the new lines and at the same time the viewer application locks the file for reading.
The Service Code:
void WriteInLog(string logFilePath, data)
{
File.AppendAllText(logFilePath,
string.Format("{0} : {1}\r\n", DateTime.Now, data));
}
The viewer Code:
int index = 0;
private void Form1_Load(object sender, EventArgs e)
{
try
{
using (StreamReader sr = new StreamReader(logFilePath))
{
while (sr.Peek() >= 0) // reading the old data
{
AddLineToGrid(sr.ReadLine());
index++;
}
sr.Close();
}
timer1.Start();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
private void timer1_Tick(object sender, EventArgs e)
{
using (StreamReader sr = new StreamReader(logFilePath))
{
// skipping the old data, it has read in the Form1_Load event handler
for (int i = 0; i < index ; i++)
sr.ReadLine();
while (sr.Peek() >= 0) // reading the live data if exists
{
string str = sr.ReadLine();
if (str != null)
{
AddLineToGrid(str);
index++;
}
}
sr.Close();
}
}
Is there any problem in my code in reading and writing way?
How to solve the problem?

You need to make sure that both the service and the reader open the log file non-exclusively. Try this:
For the service - the writer in your example - use a FileStream instance created as follows:
var outStream = new FileStream(logfileName, FileMode.Open,
FileAccess.Write, FileShare.ReadWrite);
For the reader use the same but change the file access:
var inStream = new FileStream(logfileName, FileMode.Open,
FileAccess.Read, FileShare.ReadWrite);
Also, since FileStream implements IDisposable make sure that in both cases you consider using a using statement, for example for the writer:
using(var outStream = ...)
{
// using outStream here
...
}
Good luck!

Explicit set up the sharing mode while reading the text file.
using (FileStream fs = new FileStream(logFilePath,
FileMode.Open,
FileAccess.Read,
FileShare.ReadWrite))
{
using (StreamReader sr = new StreamReader(fs))
{
while (sr.Peek() >= 0) // reading the old data
{
AddLineToGrid(sr.ReadLine());
index++;
}
}
}

new StreamReader(File.Open(logFilePath,
FileMode.Open,
FileAccess.Read,
FileShare.ReadWrite))
-> this doesn't lock the file.

The problem is when you are writing to the log you are exclusively locking the file down so your StreamReader won't be allowed to open it at all.
You need to try open the file in readonly mode.
using (FileStream fs = new FileStream("myLogFile.txt", FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
{
using (StreamReader sr = new StreamReader(fs))
{
while (!fs.EndOfStream)
{
string line = fs.ReadLine();
// Your code here
}
}
}

I remember doing the same thing a couple of years ago. After some google queries i found this:
FileStream fs = new FileStream(#”c:\test.txt”,
FileMode.Open,
FileAccess.Read,
FileShare.ReadWrite);
i.e. use the FileShare.ReadWrite attribute on FileStream().
(found on Balaji Ramesh's blog)

Have you tried copying the file, then reading it?
Just update the copy whenever big changes are made.

This method will help you to fastest read a text file and without locking it.
private string ReadFileAndFetchStringInSingleLine(string file)
{
StringBuilder sb;
try
{
sb = new StringBuilder();
using (FileStream fs = File.Open(file, FileMode.Open))
{
using (BufferedStream bs = new BufferedStream(fs))
{
using (StreamReader sr = new StreamReader(bs))
{
string str;
while ((str = sr.ReadLine()) != null)
{
sb.Append(str);
}
}
}
}
return sb.ToString();
}
catch (Exception ex)
{
return "";
}
}
Hope this method will help you.