How to handle an Image that is null in vb.net

Question

I have this working code that displays an image in the other form when datagridview is selected

Private Sub dgv1_DoubleClick(sender As Object, e As EventArgs) Handles dgv1.DoubleClick
            frmEdit.Show()
            Dim ms As New MemoryStream(changephoto(CInt(dgv1.SelectedCells(0).Value)))
            frmEdit.PictureBox1.Image = Image.FromStream(ms)
    End Sub


        Function changephoto(ByVal photo As Integer) As Byte()
            cn.Open()

            With cmd
                .Connection = cn
                .CommandText = "SELECT studImage FROM studentInformation WHERE Studentid = " & dgv1.SelectedRows(0).Cells(0).Value
            End With
            Dim myPhoto() As Byte = CType(cmd.ExecuteScalar(), Byte())
            cn.Close()
            Return myPhoto
        End Function

The problem is when i select a record that has no image,I get this error:

I want the user to select records even if it is no image in the database without having error. Can anyone help me how to fix this. thanks

Answer 1

Decalre myPhoto() outside of the Try...Catch block. Additionally you should close the connection in error and non-error case (Finally or alternatively with the Using keyword).

Dim myPhoto() as Byte = Nothing
With cmd
    .Connection = cn
    .CommandText = "SELECT studImage FROM studentInformation WHERE Studentid = " & dgv1.SelectedRows(0).Cells(0).Value
End With

Try
  cn.Open()
  myPhoto = CType(cmd.ExecuteScalar(), Byte())
Catch ex as Exception

Finally
  If cn IsNot Nothing
     cn.Close()
  End If
End Try
return myPhoto

EDIT:

Private Sub dgv1_DoubleClick(sender As Object, e As EventArgs) Handles dgv1.DoubleClick
    frmEdit.Show()
    Dim ms As MemoryStream
    Dim photo as Byte() = changephoto(CInt(dgv1.SelectedCells(0).Value))
    If photo IsNot Nothing
       ms = new MemoryStream(photo)
       frmEdit.PictureBox1.Image = Image.FromStream(ms)
    End If
End Sub