Date Comparison in C#

using System;
using System.Globalization;

public class Helper
{
    /// Returns -1 if StartDate less than EndDate, 
    /// 0 if Equal.
    /// 1 if StartDate greater than EndDate  
    public static int CompareDates(string strStartDate, string strEndDate)
    {
        try
        {
            // Creates and initializes the CultureInfo which uses the international sort.
            //I have used English (United Kingdom) cultural inforamtion to convert data into dd/MM/yyyy format 
            CultureInfo cultInfo = new CultureInfo("en-GB", true);
            DateTimeFormatInfo formatInfo = cultInfo.DateTimeFormat;

            formatInfo.ShortDatePattern = "dd/MM/yy";
            formatInfo.ShortDatePattern = "dd/MM/yyyy";
            formatInfo.LongDatePattern = "dd MMMM yyyy";
            formatInfo.FullDateTimePattern = "dd MMMM yyyy HH:mm:ss";

            DateTime startDate = new DateTime();
            DateTime endDate = new DateTime();

            //Convert strStartDate which is passed as string argument into date
            if (!String.IsNullOrEmpty(strStartDate))
                startDate = System.Convert.ToDateTime(strStartDate, formatInfo);

            //Convert strEndDate which is passed as string argument into date
            if (!String.IsNullOrEmpty(strEndDate))
                endDate = System.Convert.ToDateTime(strEndDate, formatInfo);

            return DateTime.Compare(startDate, endDate);
            

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

protected void Button1_Click(object sender, EventArgs e)
    {
        string stDate = "20/04/2009";
        string enDate = "11/06/2009";
        int result = Helper.CompareDates(stDate, enDate);

        if (result < 0)
            Response.Write(stDate + " is less than " + enDate);
        else if (result == 0)
            Response.Write(stDate + " is equal to " + enDate);
        else
            Response.Write(stDate + " is greater than " + enDate);

    }