''' 

''' event handler for Button that downloads 
''' myfile.txt from a subfolder called Data in the current directory.
''' 
Public Overrides Sub ${Download Button Control}_Click(ByVal sender As Object, ByVal args As EventArgs)

  ' Specify the name of the file, located in the
  ' file system, that needs to be downloaded.    
  Dim fileName As String = "myfile.txt" 

  ' Check if file exists in the file system.
  Dim fileExists As Boolean = System.IO.File.Exists(Me.Page.Server.MapPath("..\Data") + "\" + fileName) 
  If fileExists Then 

    ' Set up file stream object.
    Dim fs As System.IO.FileStream 
    fs = New System.IO.FileStream( _
              Me.Page.Server.MapPath("..\Data") + "\" + fileName, _
              System.IO.FileMode.Open, _
              System.IO.FileAccess.Read, _
              System.IO.FileShare.Read) 

    Dim fullFileName As String = Me.Page.Server.MapPath("..\Data") + "\" + fileName 
    Try 

      ' Read the contents of the file.
      Dim bufSize As Integer = CType(fs.Length, Integer) 
      Dim buf(bufSize) As Byte 
      Dim bytesRead As Integer = fs.Read(buf, 0, bufSize) 

      ' Set up parameters for file download.
      Me.Page.Response.ContentType = "application/octet-stream" 
      Me.Page.Response.AppendHeader("Content-Disposition", "attachment;filename=" + fileName) 

      ' Download the file.
      Me.Page.Response.OutputStream.Write(buf, 0, bytesRead) 
      Me.Page.Response.Flush() 
      
    Catch ex As Exception
    
      ' Report the error message to the user
      Utils.MiscUtils.RegisterJScriptAlert(Me, "UNIQUE_SCRIPTKEY", ex.Message)
      
    Finally 
      fs.Close 
    End Try 
  Else 
    Me.Page.Response.Write("File cannot be found to download") 
  End If
 
End Sub