How can I retrieve binary data from sql with c#?

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**
}

Noldorin · Accepted Answer · 2009-08-27 10:27:12Z

4

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.

answered Aug 27, 2009 at 10:27

Noldorin

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5 Comments

Mary Over a year ago

Please Help i have blow code: FileStream fs = new FileStream(path, FileMode.OpenOrCreate, FileAccess.Write); Path.GetTempFileName(); fs.Write(b, 0, b.Length); fs.Flush(); fs.Close(); i dont now satrt fs if Process.Start(fs.Name)? but it start app with same path that exit not from sql

Mary Over a year ago

but it start file with same path that exist not from read byte from sql

Will Marcouiller Over a year ago

This is a very useful answer. I didn't even know the existance of such a method. Thanks!

Noldorin Over a year ago

@Mary: You should be assigning path = Path.GetTempFileName(); and then use Process.Start(path).

Noldorin Over a year ago

@Mary: If you have everything working now, would you mind accepting the answer?

Nathan Baulch · Accepted Answer · 2009-08-27 11:33:07Z

1

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.

edited Aug 27, 2009 at 11:33

answered Aug 27, 2009 at 11:11

Nathan Baulch

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6 Comments

Mary Over a year ago

thanx for answer but when run this codes one temp file with tmp extention creat and error occurd: No application is associated with the specified file for this operation please help me thanx

Nathan Baulch Over a year ago

See the amendment to my answer regarding file extensions.

Mary Over a year ago

my extetention files is txt or doc or docx where i append my extetion to tempfile?

Nathan Baulch Over a year ago

I have changed the code so that the temp file extension is "txt". You still need some way to determine if you're dealing with plain text or an MS Word document.

Mary Over a year ago

very thanx for your HElp Thanxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx :-)

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