如何将字节数组读入FileStream

Question

I have an byte array and I want to read the byte array into a FileStream. Below is my sample of code:

string fileName = "test.txt";
byte[] file = File.ReadAllBytes(Server.MapPath("~/Files/" + fileName));
FileStream fs = new FileStream();
fs.ReadByte(file);
object obj = LoadFile<object>(fs);

public static T LoadFile<T>(FileStream fs)
{
    using (GZipStream gzip = new GZipStream(fs, CompressionMode.Decompress))
    {
        BinaryFormatter bf = new BinaryFormatter();
        return (T)bf.Deserialize(gzip);
    }
}

In the method above, I have use FileStream to read byte array, but unlucky fs.ReadByte cannot read byte array. Any help please focus on how to Read byte array into a FileStream for using as a parameter in method "LoadFile". Please do not read directly the file into FileStream because the file here is loaded from somewhere else like from database or other source.

Answer 1

string fileName = "test.txt";
byte[] file = File.ReadAllBytes(Server.MapPath("~/Files/" + fileName));
MemoryStream memStream = new MemoryStream();
BinaryFormatter binForm = new BinaryFormatter();
memStream.Write(file, 0, file.Length);
memStream.Seek(0, SeekOrigin.Begin);
Object obj = (Object)binForm.Deserialize(memStream);

Answer 2

I'm not sure where the misunderstanding is. FileStream represents a file on disk. You cannot "read bytes into it" without writing them to disk and you cannot read from it without reading from disk.

Maybe what you want is a MemoryStream which can contain arbitrary contents.

Both derive from Stream.

Answer 3

Why do you run File.ReadAllBytes prior to the usage of your FileStream ?

string fileName = "test.txt";
using(FileStream fs = new FileStream(Server.MapPath("~/Files/" + fileName), FileMode.Open, FileAccess.Read))
{
    object obj = LoadFile<object>(fs);
    fs.Close();
}

Answer 4

Yeah! Now I got a good solution after doing some more research. As the topic I have posted "How to read byte array into FileStream". We cannot read byte array into FileStream, it just use to read a file on driver to byte array. So I have change a little bit on my code, and now I have a file to read it using FileStream. How I made a file?

In this context I have an object. The object is anything as you want!

I use a collection as a samble object.

Collection<object> list = new Collection<object>();
//Now I will write this list to a file. fileName is what you want and be sure that folder Files is exist on server or at the root folder of your project
WriteFile(list, Server.MapPath("~/Files/" + fileName));
//The method to write object to file is here
public static void WriteFile<T>(T obj, string path)
{
    FileStream serializeStream = new FileStream(path, FileMode.Create);
    BinaryFormatter bf = new BinaryFormatter();
    bf.Serialize(serializeStream, obj);
    serializeStream.Flush();
    serializeStream.Close();
}

After I have wrote my object to a file, I need a method to read it back to object. So I do write this method:

public static Collection<object> ReatFile(string fileName){
            //I have to read the file which I have wrote to an byte array            
            byte[] file;
            using (var stream = new FileStream(Server.MapPath("~/Files/" + fileName), FileMode.Open, FileAccess.Read))
            {
                using (var reader = new BinaryReader(stream))
                {
                    file = reader.ReadBytes((int)stream.Length);

                }

            }
            //And now is what I have to do with the byte array of file is to convert it back to object which I have wrote it into a file
            //I am using MemoryStream to convert byte array back to the original object.
            MemoryStream memStream = new MemoryStream();
            BinaryFormatter binForm = new BinaryFormatter();
            memStream.Write(file, 0, file.Length);
            memStream.Seek(0, SeekOrigin.Begin);
            Object obj = (Object)binForm.Deserialize(memStream);
            Collection<object> list = (Collection<object>)obj;
            return list;
}

After doing some steps above, I am now can write any type object to file and then read it back to original object. Thank too much for any help I have got there.