title: check data reader null or not in while condition
body: <p>i have a query like this:</p>
  
  <pre><code>Dim dr As SqlDataReader
      Dim str As String = "SELECT DISTINCT Location_tbl.LocName, Location_tbl.Locid FROM Transaction_tbl"
       Dim cmd As New SqlCommand(str, con.connect)
              dr = cmd.ExecuteReader
              While dr.Read
                 ChkdLST.Visible = True
                  ChkdLST.Items.Add(dr("LocName"))
              End While
              dr.Close()
              con.disconnect()
  </code></pre>
  
  <p>if reader contains any data then only i want to make chkdlst visible..so i want to check my datareader is null or not in the stage of  <code>While dr.Read</code>   if contains data then should visible else i have to make  ChkdLST.Visible = false..so how i can check <code>while dr.read</code> contains data or not</p>