Invalid attempt to read when no data is present?

when execute

If IsDBNull(sqlreader.GetValue(i)) Then

Error info:Invalid attempt to read when no data is present

but i am sure there were records

Any ideas? Regards

Have you checked sqlreader.Read() is true?|||

it's ture,below is my code

For i = 1 To sqlreader.FieldCount - 1
If IsDBNull(sqlreader.GetValue(i)) = false Then
Row.fieldname = Trim(sqlreader.GetName(i).ToString())
Row.fieldvalue = Trim(sqlreader.GetString(i))
End If
Next

both fieldcount and getname are right