如何使用C＃从SQL检索二进制数据？

Question

I retrieved the data that I saved in a filestream column as an example the below code, and got it into memory stream or byte array. How can I open it with its default?

OS application like opening a photo with photo manager or word document with MS Word ? Normally I use the Process.Start command but it doesn't work with memorystream or byte array so how can this be done ?

 public DataTable RetriveFile(int Code)
        {
            mydbms d = new mydbms();
            DataTable dt;


           String com2 = "select * from Matn_Naame where Code=" + Code + ";";
           dt = d.executeselectsql(com2);


            return dt;
        }
{
Letter_Manager L_M = new Letter_Manager();
            Byte[] b;
            DataTable dt = new DataTable();
            dt = L_M.RetriveFile(6);

            b=(Byte[])dt.Rows[0]["fileContent"];
            path = dt.Rows[0]["Path"].ToString();

                 MemoryStream Memory = new MemoryStream(b);
                 Memory.Write(b, 0, b.Length);
//??????????????????**?for open and show file**
}

Answer 1

You will need to save the data to a temporary file. A temporary filename is available by calling System.IO.Path.GetTempFileName() . You can then simply use a FileStream to save to that path, and as you mentioned, Process.Start to launch the default application.

Answer 2

The easiest way is to use the convenient File.WriteAllBytes method which writes a byte array directly to the file name specified.

var fileName = Path.ChangeExtension(Path.GetTempFileName(), "txt");
File.WriteAllBytes(fileName, b);
Process.Start(fileName);

Note that in my example I have assumed that you are dealing with plain text data that you wish to open with the default text editor.

Windows will not know what application to launch this file unless you give it a meaningful extension. You either have to know the format of the data upfront so you can append the correct extension or you'll need to use a library that can guess what kind of data it is such as the excellent TrID file identification tool.