I may have become familiar with the FileStream library type. How does the Lock method work? Can anyone provide me some examples? Which parameters and their data types do I need to make this work properly? Regards, John

To lock part of a file use FileStream.Lock method which has two parameters, start of range and length of range to lock then to unlock use Unlock . Both methods have code samples to learn from.

Locking part or last byte of a binary file

Accepted answer

Karen Payne MVP 35,401 Reputation points

2021-06-17T12:05:15.57+00:00

To lock part of a file use FileStream.Lock method which has two parameters, start of range and length of range to lock then to unlock use Unlock. Both methods have code samples to learn from.
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1 person found this answer helpful.
John 466 Reputation points

2021-06-18T02:47:31.33+00:00

Okay. The source code snippet example demonstrate what only refers to text files or text file streams.

Can anyone provide me some code snippet examples, which refer to binary files or binary file streams?

Regards,

John-1477

Cheong00 3,476 Reputation points

2021-06-18T03:02:39.287+00:00

FileStream is for use of generic file stream (you see the code use uniEncoding.GetBytes() or uniEncoding.GetChars() to convert between bytes being read/write and the string content right?)

John 466 Reputation points

2021-06-18T04:29:02.537+00:00

Probably the Binary Reader and Binary Writer type.

If audio and video files are considered binary, then the Binary Reader and Binary Writer type, which is part of the System.IO library service, should work.

If it does work, then can anyone provide me some code snippet examples?

Regards,

John-1477

John 466 Reputation points

2021-06-18T05:22:40.853+00:00

This is a code snippet below that might work. Compile and run it if it is possible. If it does not during runtime, let me know.
private void ReadLocker()
{
try
{
Console.WriteLine("Preparing to Read Lock...");

//Open a FileStream in Read mode FileStream fin = new FileStream("AboutThisTrack.wav", FileMode.Open, FileAccess.Read, FileShare.ReadWrite); //Create a BinaryReader from the FileStream BinaryReader br = new BinaryReader(fin); //Seek to the start of the file br.BaseStream.Seek(0, SeekOrigin.Begin); //Read from the file and store the values to the variables br.Lock(); Console.WriteLine("Binary Track Stream is Read Locked!"); } catch (IOException e) { Console.WriteLine("An IO Exception Occurred :" + e); }

}

Cheong00 3,476 Reputation points

2021-06-18T06:16:24.623+00:00

BinaryReader does not provide .Lock() method.

To use Locking, you should use fin,Lock(position, length) instead. To lock current byte, use fin.Lock(fin.Position, 1), to lock the final byte, uses fin.Lock(fin.Length - 1, 1) .

John 466 Reputation points

2021-06-19T22:52:48.523+00:00

I I have tried to lock the file, but it did not save or update its status.

Is there a FileSave method somewhere within the C# object model reference?

Regards,

John-1477

John 466 Reputation points

2021-06-19T23:11:28.357+00:00

I may have an idea.

What about asynchronously accessing a file prior to locking it?

Regards,

John-1477

John 466 Reputation points

2021-06-20T01:41:43.187+00:00

This code snippet compiles and runs fine, but it does not update the file's status.

string filename = @"c:\Users\...\Documents\Audio001.wav"; byte[] result; MessageBox.Show("Locking the file in progress."); using (FileStream SourceStream = File.Open(filename, FileMode.Open, FileAccess.ReadWrite)) { result = new byte[SourceStream.Length]; await SourceStream.ReadAsync(result, 0, (int)SourceStream.Length); SourceStream.Lock(0, SourceStream.Length); SourceStream.Flush(); SourceStream.Close(); } MessageBox.Show("File is locked."); } }

John 466 Reputation points

2021-06-20T03:38:36.3+00:00

Here is what I have done so far. I have tried to start a live share session, but it did not work.
Can anyone solve this code snippet problem?

Regards,

John-1477

Viorel 116.6K Reputation points

2021-06-20T05:43:15.367+00:00

Maybe you expect too much from Lock function.

John 466 Reputation points

2021-06-20T05:50:54.463+00:00

Correct. The lock function does not meet my expectations.
It does not read the file after it is locked and it behaves the same way as the exclusive lock function in C++.

The next question I have posted, recently, refers to C++ and its shared lock function.

Regards,

John-1477
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