C# DateTime Library - CodeProject

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Introduction

I recently made the transition from Delphi to C#. I noticed that some of the datetime utilities that I used to use were not available in C#. So I recreated them. Hopefully this will save someone some time in the future.

The Code

using System;
namespace Concepts2Code.Utilities
{
    /// <summary>
    /// Common DateTime Methods.
    /// </summary>
    /// 

    public enum Quarter
    {
        First = 1,
        Second = 2,
        Third = 3,
        Fourth = 4
    }

    public enum Month
    {
        January = 1,
        February = 2,
        March = 3,
        April = 4,
        May = 5,
        June = 6,
        July = 7,
        August = 8,
        September = 9,
        October = 10,
        November = 11,
        December = 12
    }

    public class DateUtilities
    {
        #region Quarters

        public static DateTime GetStartOfQuarter( int Year, Quarter Qtr )
        {
            if( Qtr == Quarter.First )    // 1st Quarter = January 1 to March 31
                return new DateTime( Year, 1, 1, 0, 0, 0, 0 );
            else if( Qtr == Quarter.Second ) // 2nd Quarter = April 1 to June 30
                return new DateTime( Year, 4, 1, 0, 0, 0, 0 );
            else if( Qtr == Quarter.Third ) // 3rd Quarter = July 1 to September 30
                return new DateTime( Year, 7, 1, 0, 0, 0, 0 );
            else // 4th Quarter = October 1 to December 31
                return new DateTime( Year, 10, 1, 0, 0, 0, 0 );
        }

        public static DateTime GetEndOfQuarter( int Year, Quarter Qtr )
        {
            if( Qtr == Quarter.First )    // 1st Quarter = January 1 to March 31
                return new DateTime( Year, 3, 
                       DateTime.DaysInMonth( Year, 3 ), 23, 59, 59, 999 );
            else if( Qtr == Quarter.Second ) // 2nd Quarter = April 1 to June 30
                return new DateTime( Year, 6, 
                       DateTime.DaysInMonth( Year, 6 ), 23, 59, 59, 999 );
            else if( Qtr == Quarter.Third ) // 3rd Quarter = July 1 to September 30
                return new DateTime( Year, 9, 
                       DateTime.DaysInMonth( Year, 9 ), 23, 59, 59, 999 );
            else // 4th Quarter = October 1 to December 31
                return new DateTime( Year, 12, 
                       DateTime.DaysInMonth( Year, 12 ), 23, 59, 59, 999 );
        }

        public static Quarter GetQuarter( Month Month )
        {
            if( Month <= Month.March )
            // 1st Quarter = January 1 to March 31
                return Quarter.First;
            else if( ( Month >= Month.April ) && ( Month <= Month.June ) )
            // 2nd Quarter = April 1 to June 30
                return Quarter.Second;
            else if( ( Month >= Month.July ) && ( Month <= Month.September ) )
            // 3rd Quarter = July 1 to September 30
                return Quarter.Third;
            else // 4th Quarter = October 1 to December 31
                return Quarter.Fourth;
        }

        public static DateTime GetEndOfLastQuarter()
        {                 
            if( (Month)DateTime.Now.Month <= Month.March )
            //go to last quarter of previous year
                return GetEndOfQuarter( DateTime.Now.Year - 1, Quarter.Fourth);
            else //return last quarter of current year
                return GetEndOfQuarter( DateTime.Now.Year, 
                  GetQuarter( (Month)DateTime.Now.Month));
        }

        public static DateTime GetStartOfLastQuarter()
        {
            if( (Month)DateTime.Now.Month <= Month.March )
            //go to last quarter of previous year
                return GetStartOfQuarter( DateTime.Now.Year - 1, Quarter.Fourth);
            else //return last quarter of current year
                return GetStartOfQuarter( DateTime.Now.Year, 
                  GetQuarter( (Month)DateTime.Now.Month));
        }

        public static DateTime GetStartOfCurrentQuarter()
        {
            return GetStartOfQuarter( DateTime.Now.Year, 
                   GetQuarter( (Month)DateTime.Now.Month ));
        }

        public static DateTime GetEndOfCurrentQuarter()
        {
            return GetEndOfQuarter( DateTime.Now.Year, 
                   GetQuarter( (Month)DateTime.Now.Month ));
        }
        #endregion

        #region Weeks
        public static DateTime GetStartOfLastWeek()
        {
            int DaysToSubtract = (int)DateTime.Now.DayOfWeek + 7;
            DateTime dt = 
              DateTime.Now.Subtract(System.TimeSpan.FromDays( DaysToSubtract ) );
            return new DateTime( dt.Year, dt.Month, dt.Day, 0, 0, 0, 0 );
        }

        public static DateTime GetEndOfLastWeek()
        {
            DateTime dt = GetStartOfLastWeek().AddDays(6);
            return new DateTime( dt.Year, dt.Month, dt.Day, 23, 59, 59, 999 );
        }

        public static DateTime GetStartOfCurrentWeek()
        {
            int DaysToSubtract = (int)DateTime.Now.DayOfWeek ;
            DateTime dt = 
              DateTime.Now.Subtract( System.TimeSpan.FromDays( DaysToSubtract ) );
            return new DateTime( dt.Year, dt.Month, dt.Day, 0, 0, 0, 0 );
        }

        public static DateTime GetEndOfCurrentWeek()
        {
            DateTime dt = GetStartOfCurrentWeek().AddDays(6);
            return new DateTime( dt.Year, dt.Month, dt.Day, 23, 59, 59, 999 );
        }
        #endregion

        #region Months

        public static DateTime GetStartOfMonth( Month Month, int Year )
        {
             return new DateTime( Year, (int)Month, 1, 0, 0, 0, 0 );
        }

        public static DateTime GetEndOfMonth( Month Month, int Year )
        {
            return new DateTime( Year, (int)Month, 
               DateTime.DaysInMonth( Year, (int)Month ), 23, 59, 59, 999 );
        }

        public static DateTime GetStartOfLastMonth()
        {
            if( DateTime.Now.Month == 1 )
                return GetStartOfMonth( 12, DateTime.Now.Year - 1);
            else
                return GetStartOfMonth( DateTime.Now.Month -1, DateTime.Now.Year );
        }

        public static DateTime GetEndOfLastMonth()
        {
            if( DateTime.Now.Month == 1 )
                return GetEndOfMonth( 12, DateTime.Now.Year - 1);
            else
                return GetEndOfMonth( DateTime.Now.Month -1, DateTime.Now.Year );
        }

        public static DateTime GetStartOfCurrentMonth()
        {
            return GetStartOfMonth( DateTime.Now.Month, DateTime.Now.Year );
        }

        public static DateTime GetEndOfCurrentMonth()
        {
            return GetEndOfMonth( DateTime.Now.Month, DateTime.Now.Year );
        }
        #endregion

        #region Years
        public static DateTime GetStartOfYear( int Year )
        {
            return new DateTime( Year, 1, 1, 0, 0, 0, 0 );
        }

        public static DateTime GetEndOfYear( int Year )
        {
            return new DateTime( Year, 12, 
              DateTime.DaysInMonth( Year, 12 ), 23, 59, 59, 999 );
        }

        public static DateTime GetStartOfLastYear()
        {
            return GetStartOfYear( DateTime.Now.Year - 1 );
        }

        public static DateTime GetEndOfLastYear()
        {
            return GetEndOfYear( DateTime.Now.Year - 1 );
        }

        public static DateTime GetStartOfCurrentYear()
        {
            return GetStartOfYear( DateTime.Now.Year );
        }

        public static DateTime GetEndOfCurrentYear()
        {
            return GetEndOfYear( DateTime.Now.Year );
        }
        #endregion        

        #region Days
        public static DateTime GetStartOfDay( DateTime date )
        {
            return new DateTime( date.Year, date.Month, date.Day, 0, 0, 0, 0 );
        }

        public static DateTime GetEndOfDay( DateTime date )
        {
            return new DateTime( date.Year, date.Month, 
                                 date.Day, 23, 59, 59, 999 );
        }
        #endregion
      }
}

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here

About the Author

Michael Ceranski

Software Developer (Senior)
Concepts2Code

United States

Member

Michael is the co-founder and master consultant for Concepts2Code, a software consulting company based in Buffalo, New York. He's been programming since the early 1990's. His vast programming experience includes VB, Delphi, C#, ASP, ASP.NET, Ruby on Rails, Coldfusion and PHP. Michael also is a Microsoft Certified Application Developer and a Certified Technology Specialist for SQL Server.

Visit his blog.

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Comments and Discussions

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This is article was very helpful

Espiritu

18:44 8 Apr '12

Thanks a lot. It came very handy at the right moment. Thank you.
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My vote of 5

Espiritu

18:43 8 Apr '12

Excellent article.
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Nice, good job

cruzanPC

5:30 2 Dec '11

Wished C# had built-in methods for Quarters (like in SQL Server) Tested this and it works perfectly for my use
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first day of week monday (International )

mindweaver

3:21 17 Jan '11

Do you think it is possible to add an option to your week functions to consider international dates. And get firstday of weeks as monday and not sunday, which infact is our last day of the week.
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Re: first day of week monday (International )

Jani Giannoudis

21:09 19 Mar '11

Hi mindweaver, I have written the Time Period Library for .NET[^], which includes support for local cultures. Jani Giannoudis Latest article: Time Period Library for .NET
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thank you very much.

Howdy Nun

11:47 20 May '09

thank you very much, your function help me very very much.
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GetEndOfLastQuarter and GetStartOfLastQuarter Problem

edwardxu888

11:29 19 Apr '09

GetEndOfLastQuarter()
GetStartOfLastQuarter()

Correct Code:

public static DateTime GetEndOfLastQuarter()
{
if( (Month)DateTime.Now.Month <= Month.March )
//go to last quarter of previous year
return GetEndOfQuarter( DateTime.Now.Year - 1, Quarter.Fourth);
else //return last quarter of current year
return GetEndOfQuarter( DateTime.Now.Year,
GetQuarter( (Month)DateTime.Now.Month) -1);
}

public static DateTime GetStartOfLastQuarter()
{
if( (Month)DateTime.Now.Month <= Month.March )
//go to last quarter of previous year
return GetStartOfQuarter( DateTime.Now.Year - 1, Quarter.Fourth);
else //return last quarter of current year
return GetStartOfQuarter( DateTime.Now.Year,
GetQuarter( (Month)DateTime.Now.Month) -1);
}

Bugs Depending On Time Of Execution

jason26535

6:45 26 Dec '08

A few of the functions should be changed to ensure that time of execution does not introduce the possibility of bugs (esp. those functions which use DateTime.Today / DateTime.Now multiple times instead of a single instance so all calculations use the same concept of Today / Now. For Example:

public static DateTime GetStartOfCurrentQuarter()
        {
            return GetStartOfQuarter( DateTime.Now.Year, 
                   GetQuarter( (Month)DateTime.Now.Month ));
        }

should be something like the following to avoid the (albeit very small) possibility that the resolution of Year and Month don't occur at midnight on a year/month boundary such that they would be in opposition; i.e. midnight on 12/31/2008, where the above could resolve to something like:

return GetStartOfQuarter(2009, GetQuarter(12)) or GetStartOfQuarter(2008, GetQuarter(1)) instead of GetStartOfQuarter(2008, GetQuarter(12))

// corrected to ensure consistent concept of 'Now':
public static DateTime GetStartOfCurrentQuarter()
        {
            DateTime dtNow = DateTime.Now;
            return GetStartOfQuarter( dtNow.Year, 
                   GetQuarter( (Month)dtNow.Month ));
        }

DateTime with zero month and day

ElGuroProgramador

2:24 6 Aug '08

I have a problem using a DateTime under these circumstances:

We use DateTime in .net and SQL Server as a birthday field.
Some people only know the year, or the year and month.
So month and day can be 0 (because unknown) and not 1 or something else.

1)
How can i use the DateTime .net object in this case?

return DateTime.ParseExact(date, "dd.MM.yyy", null); // not possible cause month or day can be 0

DateTime d = new DateTime(year, 0,0); // also not possible, month and day can not be 0

2)
param = new SqlParameter();
param.DbType = DbType.DateTime;
param.ParameterName = "@dayofBirth"; // DateTime object
param.Value = dayofBirth;

if (param.Value == null)
param.Value = DBNull.Value;

Re: DateTime with zero month and day

Michael Ceranski

9:44 12 Aug '08

The datetime class does not really allow for the month, day, or year to be a zero value. Therefore your only choice is to store each part of the datetime value in a seperate field in the database or use a string expression (like "MMDDYYYY") in order to represent a partial date. For example a string like "11002008" would mean november 2008 with no value for the day.

From a programming perspective you may want to create an object class similar to this to use in your application

public class PartialDateTime
{
public int? Day { get; set; }
public int? Month { get; set; }
public int? Year { get; set; }
}

Using this class you could create a partial date like this:

new PartialDateTime{ Day = null, Month = 11, Year = 2008 }

If you decide to store the partial date in the database as a string pattern of MMDDYYYY you could override the ToString() method. This way when you are setting the database parameters you could easily "deserialize" the value to the database. You could also create a constructor to take the MMDDYYYY pattern which would initiliaze the Day, Month and Year values.

Thanks!

JohnnyHax

15:33 24 Apr '08

Very nice of you to share your work. I am using it in my app. Thanks.
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Toad uses my library

Michael Ceranski

5:57 9 Apr '08

I recently found out from a developer at Quest that they are using my C# datetime utilities in Toad for SQL Server. It is always cool to find out where your code is being used. Especially with a premier product like TOAD!!!
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Delphi x C# (Incompatibility)

vinny_cwb

2:27 14 Mar '08

Hi,

I'm creating a library in C# that encrypts a set of data using a DateTime as key. The problem is:

When the TotalDays of a date is calculated in Delphi, it uses the days difference between 31/12/1899 12:00am and my date, for example 07/03/2008 13:46:22 (my date format is dd/MM/yyyy hh:mm:ss).

When I calculate this difference with C# (using the TimeSpan), it produces a difference of 0.5 days to Delphi TDateTime.

Make a test, creating a TDateTime in Delphi with the value 07/03/2008 13:46:22, and in C# do this:

DateTime startDate = new DateTime(1899,12,31,12,00,00);
DateTime endDate = new DateTime(2008,03,07,13,46,22);
TimeSpan difference = endDate - startDate;

Console.WriteLine(difference.TotalDays.ToString());

The formula of get fractional days of C# (TimeSpan.TotalDays) is different of Delphi formula. Do you know how can I fix this?

Thank you.

011269

0:10 3 Oct '07

Very helpful. Best regards.
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Please help

his_richness

18:01 16 Nov '06

I can't figure out what I've done wrong!!! Quite annoying.
I've got a webpage that's got a calendar control on it that's connected to a repeater that retrieves data from that month and only that month of the data. It seems to compile right and everything, but it comes up with no data when I run it in the form of the repeater.
I'm assuming it's because of the date format or something. Everything to do with my computer is in dd/mm/yyyy format.
Please can someone help me figure out what's wrong with this?
Here's my code for my view.aspx page:

using System;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

public partial class View : System.Web.UI.Page
{
protected DataSet dsAd;
protected void Page_Load(object sender, EventArgs e)
{
if (!User.Identity.IsAuthenticated)
{
Response.Redirect("Default.aspx");
}

if (!IsPostBack)
{
Calendar1.VisibleDate = DateTime.Today;
AdsDataset();
}
}

protected void AdsDataset()
{
DateTime firstDate = new DateTime(Calendar1.VisibleDate.Year,
Calendar1.VisibleDate.Month, 1);
DateTime lastDate = GetFirstDayOfNextMonth();
dsAd = GetCurrentMonthData(firstDate, lastDate);
}

protected DateTime GetFirstDayOfNextMonth()
{
int monthNumber, yearNumber;
if (Calendar1.VisibleDate.Month == 12)
{
monthNumber = 1;
yearNumber = Calendar1.VisibleDate.Year + 1;
}
else
{
monthNumber = Calendar1.VisibleDate.Month + 1;
yearNumber = Calendar1.VisibleDate.Year;
}
DateTime lastDate = new DateTime(yearNumber, monthNumber, 1);
return lastDate;
}

protected DataSet GetCurrentMonthData(DateTime firstDate, DateTime lastDate)
{
DataSet dsMonth = new DataSet();
ConnectionStringSettings cs;
cs = ConfigurationManager.ConnectionStrings["ConnectionString1"];
String connString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
SqlConnection dbConnection = new SqlConnection(connString);
String query;
query = "SELECT * FROM Advertising WHERE DateAdded >= '" + firstDate + "' AND DateAdded <= '" + lastDate + "'";
SqlCommand dbCommand = new SqlCommand(query, dbConnection);

SqlDataAdapter sqlDataAdapter = new SqlDataAdapter(dbCommand);
try
{
sqlDataAdapter.Fill(dsMonth);
Repeater1.DataSource = dsMonth;
Repeater1.DataBind();
}
catch
{

}
return dsMonth;
}

protected void Calendar1_DayRender(object sender, DayRenderEventArgs e)
{
DateTime nextDate;
if (dsAd != null)
{
foreach (DataRow dr in dsAd.Tables[0].Rows)
{
nextDate = (DateTime)dr["AD"];
if (nextDate == e.Day.Date)
{
e.Cell.BackColor = System.Drawing.Color.Pink;
}
}
}
}
protected void Calendar1_VisibleMonthChanged(object sender,
MonthChangedEventArgs e)
{
AdsDataset();
}

protected void Calendar1_SelectionChanged(object sender, EventArgs e)
{
int myMonth = Calendar1.SelectedDate.Month;
}
}

Re: Please help

Michael Ceranski

10:19 21 Nov '06

The major problem that I see with your code resides in the GetCurrentMonthData method. You are building the sql by appending strings together instead of using parameterized sql statements. Therefore when you do this:

"SELECT * FROM Advertising WHERE DateAdded >= '" + firstDate + "' AND DateAdded <= '" + lastDate + "'";

You are forcing the firstDate variable to be casted to a string. My guess would be that the toString method for a date is probably not in the desired format. Therefore I would modify your code to use the following

SqlCommand dbCommand = new SqlCommand("SELECT * FROM Advertising WHERE DateAdded >= @firstDate AND DateAdded <= @lastDate", dbConnection);

 

dbCommand.Parameters.AddWithValue( "@firstDate", firstDate );

dbCommand.Parameters.AddWithValue( "@lastDate", lastDate );

By using parameters you will have a better chance of getting back the correct results. Even if this doesn't fix your problem, in general I would recommend using parameterized sql statements. It is easier to read, maintain and will save you from the trouble of worrying about escaping single quotes.

As an alernative, if you want to try to fix this without using parameterized sql statments, you could use the toString method of the datetime class and specify the date time format that you want to use. For example:

firstDate.toString( 'MM/dd/yyyy' )
or
firstDate.toString( 'dd/MM/yyyy' )

SQL Server Trips Over This...

MikeYeager

10:50 12 Mar '06

Thanks for the great utilities. You saved me a lot of time! I noticed that the code does not perform correctly when used with SQL Server. This is not an error in your code, but rather an anomoly with SQL Server. This query (run in query analyzer) will include records from 3/1/2006:

SELECT *
FROM orders
WHERE datetime BETWEEN '02/01/2006 00:00:00' AND '02/28/2006 23:59:59.999'

If you strip off the last "9", it runs as expected. I modified my copy of the code to only add 99 instead of 999 to the GetEndOfXXXX() methods.

Mike

Date Format Problem

Sivagnanam

0:15 28 Feb '06

Hi,
I am facing a date format problem while doing globalization.I am setting the regional setting as German. I am converting a date into the format 'dd-MMM-yyyy'(the middle tyre of my project supports only this format) using my C# code. say for example consider the date 25-03-2005. The name for the month of March in German is März. While converting to the above said format,.NET is not understading the spl character in the name of the month. So it converts March into 'Mrz'. The result of formatting is 25-Mrz-2005. But the database (either oracle or Sqlserver) can't understand 'Mrz', it can understand only 'Mär'. For the month of March, i can't do anything with my application. How to solve it? But the constraint is the date format should be dd-MMM-yyyy. Kindly help me to resolve this.

With Love
Siva.

More suggestions

Richard Cleaver

3:42 28 Dec '05

Some refactoring fun...

How about:

public DateTime StartOfThisQuarter(DateTime date) {
return (new DateTime(date.Year, (int)Math.Ceiling(date.Month / 3D) * 3 - 2, 1));
}

public DateTime StartOfLastQuarter(DateTime date) {
return (new DateTime(date.Year, (int)Math.Ceiling(date.Month / 3D) * 3 - 2, 1)).AddMonths(-3);
}

public DateTime StartOfLastMonth(DateTime date) {
return date.AddDays(-date.Day + 1).AddMonths(-1);
}

etc. etc.

Still thinking about Start/End of Week...

Re: More suggestions

Omer van Kloeten

10:06 28 Dec '05

Seconded. I think typing the conditions, rather than using simple math is a little wasteful, given that the values will never change. Plus, it would leave you with less code.

I'd have coded methods like this:

public static Quarter GetQuarter( Month Month )
{
    return ((Quarter)((int)Month / 3));
}
 
public static DateTime GetStartOfQuarter( int Year, Quarter Qtr )
{
    return new DateTime(Year, (int)Qtr * 3 - 2, 1, 0, 0, 0, 0);
}

(sorry, but I haven't run those through a compiler, but you get the general idea... Smile | :)

)

Programming is life,
The rest is mere details.

Omer van Kloeten

What am I doing wrong?

mdengler

7:03 16 Dec '05

Has anyone tried to compile this code? When I try, I receive the following error:

C:\Visual Studio Projects\aji\Utility\DateUtil.cs(61): The type or namespace name 'Quarters' could not be found (are you missing a using directive or an assembly reference?)

I wasn't quite sure what to do, but I changed all occurance of "Quarters" to "Quarter". After recompiling, I started gettting the following:

C:\Visual Studio Projects\aji\Utility\DateUtil.cs(76): No overload for method 'GetEndOfQuarter' takes '3' arguments

and

C:\Visual Studio Projects\aji\Utility\DateUtil.cs(78): The best overloaded method match for 'aji.Utility.DateUtil.GetQuarter(aji.Utility.Month)' has some invalid arguments

and

C:\Visual Studio Projects\aji\Utility\DateUtil.cs(78): Argument '1': cannot convert from 'int' to 'aji.Utility.Month'

Any help would be appreciated. Thanks to all that reply.

Re: What am I doing wrong?

Michael Ceranski

4:13 18 Dec '05

Can you post the code that is causing the error? I am speculating from the error messages that you are not passing the proper parameters to the methods. However, it is impossible to tell hat the errors are without seeing the code.
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Re: What am I doing wrong?

mdengler

4:50 18 Dec '05

Michael, Thank you for the quick reply. To address your request regarding posting code.... I haven't got anything to post. All I'm trying to do is to take the source that I downloaded from this site and compile it. The error messages are compile errors.
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Re: What am I doing wrong?

KenGuru

22:19 19 Dec '05

Try to put a `using Concepts2Code.Utilities` in your .cs file you use the lib from. And put a reference to the library. Live is to short to be angered about lost chances!
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Re: What am I doing wrong?

mdengler

3:14 20 Dec '05

Thanks KenGuru but Michael has corrected the bugs and forwarded the corrected version to me. He will be making this version available soon on this site. Thanks again for your response.
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