Convert SQL Date time format to String

when reading SQl Date time field , only i can take the date with time ..how to get only date in to text box from Ajax or some method.

this is what i need to do

http://i.stack.imgur.com/n0fgG.jpg

that's how I'm taking the date to text box.

    protected void ddlBatch_SelectedIndexChanged(object sender, EventArgs e)
    {
        String strConnString = ConfigurationManager.ConnectionStrings["CBConnectionString"].ConnectionString;
        const String strQuery = "select ItemIdentityCode, Qty, PurchasingPrice, ExpireDate, DiscountRate, IssueMode,  Principle, Force from DEL_PurchasesLines where BatchNumber = @BatchNumber";
        SqlConnection conPR = new SqlConnection(strConnString);
        SqlCommand cmdPR = new SqlCommand();
        cmdPR.Parameters.AddWithValue("@BatchNumber", ddlBatch.SelectedItem.Value);
        cmdPR.CommandType = CommandType.Text;
        cmdPR.CommandText = strQuery;
        cmdPR.Connection = conPR;
        try
        {
            conPR.Open();
            SqlDataReader sdr = cmdPR.ExecuteReader();
            while (sdr.Read())
            {

                tHFExpiaryDate.Text = sdr["ExpireDate"].ToString();

            }
        }
        catch (Exception ex)
        {
            //throw ex;
        }

        finally
        {
            conPR.Close();
            conPR.Dispose();
        }
    }