Download a byte to its original file format, and save to local drive

Question

I have made an application which allows me to save a file temporarily as a bunch of bytes in an array. I have this available to me in C# as entity.FileUpload

I have another entity called: entity.Type which specifies if it is a PDF, DOCX, XLSX and so on... but for the sake of the question, ill only use PDF's

now from this stage, I want to be able to:

1. convert the entity.FileUpload from its bunch of bytes, to a PDF and then...
2. Save it on my computer under "C:/Temp";

So my question is: is it possible to convert this byte to a pdf, and then download it locally to my machine? and if yes how would I go about achieving this

If I require different blocks of code for different file types then that is ok, I can progress onto that at a later date, thankyou for any help on this matter

what data I can see under entity.FileUpload:

How the file is saved:

I am using Javascript on the front end to save to a local database within the application as shown below:

  msls.readFile(screen, '.pdf', function (file, data) {

        var pdf = myapp.activeDataWorkspace.LocalDatabase.Enquiries.addNew();

        pdf.FileName = file.name;
        pdf.Type = file.type;
        pdf.FileUpload= data;

        myapp.activeDataWorkspace.LocalDatabase.saveChanges().done(function () {
            msls.showMessageBox('PDF ' + file.name + ' imported.');
        }, function (error) {
            msls.showMessageBox(error[0].message, { title: "Save Changes Error" });
        });
    });

• the local database is for testing purposes called "LocalDatabase"
• the table is called "Enquiries"

Answer 1

Try something like this:

        SqlCommand cmd;
        SqlConnection conn;
        SqlDataReader dr;
        string FileName = "";
        string FileType = "";

        //Get FileName And Type
        cmd = new SqlCommand("SELECT FileName, FileType FROM YourTable WHERE YourCondition", conn);
        dr = cmd.ExecuteReader();
        while (dr.Read())
        {
            FileName = dr["FileName"].ToString();
            FileType = dr["FileType"].ToString();
        }

        //Load the varbinary into a datatable
        cmd = new SqlCommand("SELECT FileData FROM YourTable WHERE YourCondition", conn);
        DataTable dt = new DataTable();
        dr = cmd.ExecuteReader();
        dt.Load(dr);    

        //Extract the rows into a byte array
        byte[] stream = (byte[])dt.Rows[0][0];

        //Re-create the file from the byte array
        File.WriteAllBytes(@"C:\Temp\" + FileName + FileType, stream);