如何将字节数组列表写入文件C＃

Question

I have an uploader that I use to split files up and upload them to my sql server. I then download each chunk and create a temporary file. I am trying to write a list of byte arrays(byte[]) into one file to recreate that file. This is because when I try to read the list of byte arrays into one array, I get an OutOfMemory exception. I am just wondering what the best way to do this is. Thanks!

 string path = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
        int currentRowSelection = fUS_FileDataGridView.CurrentCell.RowIndex;
        var totalNumber = fUS_FileDataGridView.Rows[currentRowSelection].Cells[6].Value;
        for (int i = 1; i < 149; i++)
        {
            using (var stream1 = new FileStream(path + @"\" + i + ".zip", FileMode.Open, FileAccess.Read))
            {
                using (var reader = new BinaryReader(stream1))
                {
                    list_.Add(reader.ReadBytes((int)stream1.Length));
                    stream1.Close();
                    stream1.Dispose();
                    reader.Close();
                    reader.Dispose();

                }
            }
        }
        //array_ = list_.SelectMany(a => a).ToArray();

        filePaths_ = @"C:\Users\ATLAS\Desktop\13\fun.zip";
        foreach (byte[] bytes in list_)
        {
            var doc = System.Text.Encoding.Default.GetString(bytes);
            string textToAdd1 = bytes.ToString();
            try
            {
                using (FileStream fs = File.Create(filePaths_))
                using (StreamWriter writer = new StreamWriter(fs, Encoding.Default, 512))
                {
                    writer.Write(textToAdd1);
                    writer.Close();
                    writer.Dispose();
                }
            }
            finally
            {
            }
        }
    }

Update: my question is different from the others I have found because I cannot put my list of byte arrays into a single array to write a file. I am currently only getting a 1 KB file out of my code where I should be getting a 100KB file.

Update 2: The code below makes much more sense but now I am getting a "stream was not writable error"

filePaths_ = @"C:\Users\ATLAS\Desktop\13\fun.zip";
        using (FileStream fs = File.Create(filePaths_))
        for (int i = 0; i < 151; i++)
        {
            using (var stream1 = new FileStream(path + @"\" + i + ".zip", FileMode.Open, FileAccess.Read))
            {
                using (var reader = new BinaryReader(stream1))
                {
                    using (StreamWriter writer = new StreamWriter(fs, Encoding.Default, 512))
                    {
                        writer.Write(reader);
                    }
                }
            }
        } 

Answer 1

If the problem is out of memory then you should think about how to reduce the amount of memory being used.

I don't know what your requirements are but based on the code you provided you could do all the writing inside your first foreach loop. This way you are only loading one file at a time and GC will free up the memory once you are done with each file.

    using (FileStream fs = File.AppendText(filePaths_)) 
    {
        for (int i = 1; i < 149; i++)
        {
            using (var stream1 = new FileStream(path + @"\" + i + ".zip", FileMode.Open, FileAccess.Read))
            {
                using (var reader = new BinaryReader(stream1))
                {
                    //list_.Add(reader.ReadBytes((int)stream1.Length));
                    //Instead of adding that to list, write them to disk here
                    //fs.Write(...)
                    //...


                    stream1.Close();//No need for this, using is going to call it. 
                    stream1.Dispose();//No need for this, using is going to call it. 
                    reader.Close();//No need for this, using is going to call it. 
                    reader.Dispose();//No need for this, using is going to call it. 

                }
            }
        } 
     }

Answer 2

If I right understand what do you want:

// Fill list_
List<byte[]> list_ = null;
// ....

string filePaths_ = @"C:\Users\ATLAS\Desktop\13\fun.zip";
// Create FileStream and BinaryWriter
using (var fs = File.OpenWrite(filePaths_)){
    using (var bw = new BinaryWriter(fs)){
        foreach (var bytes in list_)
            bw.Write(bytes); // Write each byte array to the stream
    }
}

Updated. You can do it in a better way, direct copy one stream to another:

string filePaths_ = @"C:\Users\ATLAS\Desktop\13\fun.zip";
// Result FileStream and BinaryWriter
using (var fs = File.OpenWrite(filePaths_))
{
    for (int i = 1; i < 149; i++)
    {
        using (var stream1 = new FileStream(path + @"\" + i + ".zip", FileMode.Open, FileAccess.Read))
        {
            // Just copy stream1 to fs
            stream1.CopyTo(fs);
        }
    }
}

Answer 3

It sounds like what you effectively want to do is append each byte array to the existing file. So I think at the time you want to write each individual array to the file you would simply open the filestream using FileMode.Append (instead of FileMode.Open).