Question

I need to open a file, deserialize a List<> of objects, remove one of the objects from the list and re-serialize the List<> back to the file without releasing a lock on the file.

Deserialization and removal of the object from the List<> is no problem, the problem comes when I try and serialize the List<> back to the file as I get the remains of the previous data… anybody any idea how to remove the remaining old data at the end of the file?

Thanks,
Paul.

Answer 1

I get the remains of the previous data

I assume that you open the file with read/write access, and that you keep it open between deserialization and serialization ? You need to :

• Open the file as read only, deserialize your data, and close the file
• Open the file as write only (without appending to it), serialize your data, and close the file

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UPDATE:

How do I keep the file locked between these two seperate operations?

Good point… in that case you could try to truncate the stream while it is open, using SetLength :

using(FileStream fs = new FileStream(path, FileMode.Open, FileAccess.ReadWrite))
{
    data = Deserialize(fs);
    DoSomething(data);

    // Truncate the file :
    fs.SetLength(0)
    fs.Position = 0;

    Serialize(fs, data);
}

(not tested)