Select DropDownList programmatically

Set by Text:

 DDL.SelectedIndex = DDL.Items.IndexOf(DDL.Items.FindByText("PassedValue"));

Set by Value: 

DDL.SelectedIndex = DDL.Items.IndexOf(DDL.Items.FindByValue("PassedValue"));

SELECT THE LATEST DATE RECORDS

Table REFILLED:

PatientID Date_refilled

3 7/6/2011

3 7/6/2011

3 2/15/2011

1 8/11/2011

1 8/2/2011

1 8//7/2011

Question: How to select the all latest date records of a patient

Output should be :

PatientID Date_refilled

1 8/11/2011

3 7/6/2011

3 7/6/2011

Here is the select command :

SELECT PatientID, date_refilled

FROM REFILLED AS t

WHERE (date_refilled =

(SELECT MAX(date_refilled) AS Expr1

FROM REFILLED

WHERE (PatientID = t.PatientID)))

ORDER BY PatientID