Question

I have a datagridview bound to a datatable. One of the columns in the Datasource is a BLOB. Its a BLOB in the database and I am retrieving all the records from the DB to the Datatable, then binding it to the DGV.

here’s a check I am to make. For the Blob columns(Documents pdfs,docs rpt txt), if there is a value other than DBNull then a button should be disabled. If other than DBNull, a buttton should be highlighted and available to download

1) How would I add a button to this DGV which is being bound to a Datatable.
2) Where and in which event should I check the value of BLOb field

Thank you
Sun

Answer 1

on your button click you will need to use this code:

     SaveFileDialog saveFileDialog1 = new SaveFileDialog();
     saveFileDialog1.Title = "Save an Image File";

     Byte[] blob = null;
     FileStream fs = null;
     blob = new Byte[(dr.GetBytes(0, 0, null, 0, int.MaxValue))];
     dr.GetBytes[0, 0, blob, 0, blob.Length);

     saveFileDialog1.ShowDialog();
     fs = (System.IO.FileStream)saveFileDialog1.OpenFile()
     fs.Write(blob, 0, blob.Length);
     fs.Close();

This will be the code to enable or disable the button

 if (dt[columnname] != dbnull.value)
 {
   button.enabled = true;

 }
 else
 {
   button.enabled = false;
 }