How to read and open files from a byte column in SQL Server?

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How to read and open files from a byte column in SQL Server?

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#1 by (2 votes)
#2 by (1 votes)

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I was able to transform my file into bytes and insert it inside a table in SQL Server, however now I want from within an application that I'm doing in C # I want to open this file. That is to reverse engineer (byte > open the file).

The code used for insertion:

Anexo a = new Anexo();
FileStream fs = new FileStream(a.Caminho, FileMode.Open, FileAccess.Read);
a.Arquivo = new byte[fs.Length];
fs.Read(a.Arquivo, 0, System.Convert.ToInt32(fs.Length));
string SQL = @"INSERT INTO ANEXO (NOME, CAMINHO, ARQUIVO) VALUES (@nome, @caminho, @arquivo)";
Cmd = new SqlCommand(SQL, Con);
Cmd.Parameters.Add("@nome", SqlDbType.VarChar).Value = a.NomeArquivo;
Cmd.Parameters.Add("@caminho", SqlDbType.VarChar).Value = a.Caminho;
Cmd.Parameters.Add("@arquivo", SqlDbType.VarBinary).Value = a.Arquivo;
Cmd.ExecuteNonQuery();

sql c# arquivo

asked by anonymous 09.12.2014 / 14:03

2 answers

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score 2 · Answer 1

Get the byte array and switch to a MemoryStream in the constructor;

Create your FileStream with the name of the file you want. I suppose you are saving at least the original file extension (the name is optional, but if you mix different files, it is worth saving a column with ".eml", ".txt", etc);

Read the bytes of MemoryStream and save in FileStream ;

If you open the file, you can call Process.Start .

// aqui está seu array de bytes
byte[] arquivo;
const int BufferSize = 65536;

// create memory stream
using (var mstrm = new MemoryStream(arquivo))
{
    using (var outStream = File.Create("resultado.eml"))
    {
        var buffer = new byte[BufferSize];
        int bytesLidos;
        while ((bytesLidos = mstrm.Read(buffer, 0, BufferSize)) != 0)
        {
            outStream.Write(buffer, 0, bytesLidos);
        }
    }
}

Editing

Use the following code to read the file in your byte array:

public byte[] FileToByteArray(string fileName)
{
    byte[] buff = null;
    FileStream fs = new FileStream(fileName, 
                               FileMode.Open, 
                               FileAccess.Read);
    BinaryReader br = new BinaryReader(fs);
    long numBytes = new FileInfo(fileName).Length;
    buff = br.ReadBytes((int) numBytes);
    return buff;
}

It ensures that you can read large files! I know your files should not be too large, but if they have large attachments they can be a problem.

To record, if it is not working, you can also use the way @Intruso pointed out too:

File.WriteAllBytes(string caminho, byte[] array)

score 1 · Answer 2

1

If your array represents a complete file:

File.WriteAllBytes(string path, byte[] bytes)

10.12.2014 / 14:51