Develop Reference

Comparing a DateTime Value to any value on a list of DateTimes in C#

I have an Appointment Scheduling Application where you set an Appointment Time and when you set that time, I want to check and see if their appointment is overlapping any other Appointment times and if So then I want to prevent them from scheduling the appointment.
I have 2 lists containing the appointment start and End Times:
public List<DateTime> AppointmentStartTimes = new List<DateTime>();
public List<DateTime> AppointmentEndTimes = new List<DateTime>();
I want them to not be able to schedule an appointment if the start time is in between any of the values on either of these lists, How would I compare the time to the values on both lists thanks?

Rather than using two lists, a cleaner / more extensible approach would be to create an Appointment class:
class Appointment
{
public DateTime StartTime { get; set; }
public DateTime EndTime { get; set; }
public bool ConflictsWith(Appointment proposed)
{
return StartTime < proposed.EndTime && proposed.StartTime < EndTime;
}
}
Then you can have a single list of appointments:
public List<Appointment> Appointments = new List<Appointment>();
And you can check for conflicts as so:
Appointment proposed = //...
bool conflicts = Appointments.Any(appointment => appointment.ConflictsWith(proposed));

My advice would be to create a class Appointment, which has a.o. a TimeFrame. A TimeFrame has a StartTime / EndTime / Duration:
interface ITimeFrame
{
DateTime StartTime {get;}
DateTime EndTime {get;}
TimeSpan Duration {get;}
}
Possible implementations:
class TimeFrame : ITimeFrame
{
public DateTime StartTime {get; set;}
public DateTime EndTime {get; set;}
public TimeSpan Duration => EndTime - StartTime;
}
But you could also choose for an Implementation where the EndTime => StartTime + Duration
interface AppointMent
{
int Id {get; }
IReadOnlyCollection<Person> Attendees {get;}
ITimeFrame TimeFrame {get; }
}
You want to know whether two Appointment overlap. I create it as extension methods of ITimeFrame and IAppointment:
public static bool Overlaps(this ITimeFrame timeFrameA, ITimeFrame timeFrameB)
{
// assuming startTime of a TimeFrame is always smaller than EndTime
// there is an overlap if
// frameA starts before frameB ends AND frameA ends after frameB starts
return timeFrameA.StartTime < timeFrameB.EndTime
&& timeFrameA.EndTime > timeFrame.StartTime;
}
public static bool Overlaps(this IAppointment appointmentA, IAppontment appointmentB)
{
return appointmentA.TimeFrame.Overlaps(appointmentB.TimeFrame);
}
Usage:
IAppointment a = ...
IAppointment b = ...
bool overlaps = a.Overlaps(b);
For LINQ we do the same with sequences:
public static bool Overlaps(
this IEnumerable<IAppointment> appointments,
IAppointment otherAppointment)
{
return appointments.Where(appointment => appointment.Overlaps(otherAppointment)).Any();
}
Usage:
IEnumerable<IAppointment> existingAppointment = ...
IAppointment requestedAppointment = ...
var hasOverlappingAppointments = existingAppointment
.Overlaps(requestedAppointment)
.Any();
if (hasOverlappingAppointments)
{
WriteMessage("Can't make this appointment, it overlaps with existing appointments");
}
else
{
AcceptAppointment(requestedAppointment);
}

AutoMapper configuration to use local time for all DateTime properties

Say I have 2 classes with the same set of properties:
public class MyDto
{
public int Id { get; set; }
public DateTime CreatedOn { get; set; }
}
public class MyViewModel
{
public int Id { get; set; }
public DateTime CreatedOn { get; set; }
}
I want to map with AutoMapper, adjusting the UTC date of the input class to local time of the output class, e.g., granted I am in UK where UTC offset currently is 1h:
var input = new MyDto {Id = 1, CreatedOn = DateTime.Parse("01-01-2015 14:30")};
var output = Mapper.Map<MyViewModel>(input); // output.CreatedOn = "01-01-2015 15:30"
Can I cofigure AutoMapper to this automatically for all DateTime properties?
N.B. to adjust the time I use DateTime.SpecifyKind(value, DateTimeKind.Utc)

You can create a custom type converter:
public class CustomDateTimeConverter : ITypeConverter<DateTime, DateTime> {
public DateTime Convert(ResolutionContext context) {
var inputDate = (DateTime) context.SourceValue;
var timeInUtc = DateTime.SpecifyKind(inputDate, DateTimeKind.Utc);
return TimeZoneInfo.ConvertTime(timeInUtc, TimeZoneInfo.Local);
}
}
This will make AutoMapper perform the conversion from UTC to local time for every mapping between two DateTime properties.

Convert TimeSpan.TotalMilliseconds to datetime and format it as hour:minute

I kinda confuse about the date time conversion
in my model i have defined
public DateTime? Sent { get; set; }
public DateTime? Reply { get; set; }
public double ResponseTime { get; set; }
in linq part i am using
ResponseTime = (u.Reply - u.sent).TotalMilliseconds
which is not formated and displayed like this 979809803
I want to know how do i convert it to datetime format, and eventually will display the format as hour:minute, for instance 2:45 between the date sent and date reply.

Just return the TimeSpan and call .ToString("hh:mm").
TimeSpan.ToString
public TimeSpan ResponseTime { get; set; }
//usage in LINQ
ResponseTime = (u.Reply - u.Sent)
When displaying...
value.ResponseTime.ToString("hh:mm")

Subtracting a DateTime from a DateTime yields a TimeSpan. Have a look at the TimeSpan.ToString Method (String) to see how you can custom format the value.
You can change ResponseTime back to a TimeSpan and from there to a string.
TimeSpan ResponseTimeSpan = new TimeSpan(0, 0, 0, (int)ResponseTime);
string ResponseTimeDisplay = ResponseTimeSpan.ToString();

Create an absolute or relative time period class in C#

I want to create some class that can calculate absolute or relative time period.
Meaning: the constructor will get either time period and units ( 3 weeks ) or two DateTime start and finish time. I have wrote the following code :
public class TimePeriod
{
public State TimePerriodState { get; private set; }
public RelativeTime RelativeTimePeriod { get; private set; }
public int UnitsOfTime { get; private set; }
public DateTime? StartTime { get; private set; }
public DateTime? EndTime { get; private set; }
public TimePeriod(RelativeTime relativeTime, int unitsOfTime)
{
TimePerriodState = State.Absolute;
RelativeTimePeriod = relativeTime;
UnitsOfTime = unitsOfTime;
}
public TimePeriod(DateTime startTime , DateTime endTime)
{
TimePerriodState = State.Relative;
StartTime = startTime;
EndTime = endTime;
}
public enum State
{
None,
Absolute,
Relative
}
public enum RelativeTime
{
None,
Hours,
Days,
Weeks,
Months,
Year
}
}
But I don't like that the usage is base on the state.
In the end the data will appear in the UI as two different controls. Is there a better way of making the API little better? Maybe pass in the data and calculate the dateTime on the fly or some thing like that?
UPDATE :
the usage is relative to any time its being used. meaning enter a timespan is not possible. lets say we need fo have the relative time prior 10 days from now or fixed days from X to Y
The TimeSpan will be calculated in a different BL class (this is a POCO class)

You're basically trying to store the same data twice.
You can define any period of time by either:
A startdate and enddate, duration can be calculated by subtraction.
A startdate and duration (TimeSpan), Enddate can be calculated by adding the two.
You could do it with a duration and enddate but that's making things harder.
What you want to do is pick one way of storing it. If you want it the other way, write a function to calculate it. E.g:
public TimePeriod(DateTime startTime , DateTime endTime)
{
StartTime = startTime;
EndTime = endTime;
}
public TimePeriod(DateTime startTime , TimeSpan length)
{
StartTime = startTime;
EndTime = startTime + length;
}
public TimeSpan GetDuration()
{
return EndTime - StartTime;
}
//Else you can just get the StartTime or EndTime variable (DateTime)

I think you have a problem with your terminology / domain understanding. Time periods are always relative by definition. An absolute time period would be a fixed date!
Can you instead use the TimeSpan struct which is part of the framework? You can then 'decorate' it in some way to indicate where this time-span was calculated from.

First of all I doubt that using some sort of UnitsOfTime is a very good idea. Try use TimeSpan instead and UI will show weeks or months. Try something like this:
public class TimePeriod
{
private readonly DateTime? _startDate;
private readonly DateTime? _endDate;
private readonly TimeSpan _timeSpan;
public TimePeriod(DateTime startDate, DateTime endDate)
{
if (_startDate > _endDate)
{
throw new ArgumentException();
}
_startDate = startDate;
_endDate = endDate;
_timeSpan = endDate - startDate;
}
public TimePeriod(TimeSpan timeSpan)
{
_timeSpan = timeSpan;
}
public TimeSpan TimeSpan
{
get { return _timeSpan; }
}
public DateTime? StartDate
{
get { return _startDate; }
}
public DateTime? EndDate
{
get { return _endDate; }
}
public bool IsAbsolute
{
get { return _startDate.HasValue; }
}
}
Also could you explain the reason why you need this class? It could help.

DateTime How To

When creating a class what is the syntax to define a public property for that class as a DateTime type rather than string?

If you want a date object, with class-controlled formatting, you need two properties:
public DateTime DateField { get; set; }
// a read only string
public String DateFieldString {
get { return DateField.ToString(/* your format */); }
}

EDIT
ASP.NET: BoundField's DataFormatString property looks to be what you want.
<asp:BoundField
DataField="EventDate"
HeaderText="Event Date"
DataFormatString="{0:MM/dd/yyyy}"/>
Easy as (pumpkin) pie. Happy Thanksgiving!

public class MyClass {
public DateTime MyDate { get; set; }
public string MyFormattedDate { get { return MyDate.ToString(myFormat); } }
}

Something like
public class TestClas
{
DateTime dtDate;
public DateTime DtDate
{
get
{
return dtDate;
}
set
{
dtDate = value;
}
}
}
and to get and set the field you can use
TestClas objDate = new TestClas();
// set date
objDate.DtDate = DateTime.Now;
// get date
DateTime dtCurDate = objDate.DtDate;
Edit
It would be better not to implement the formatting inside the property. Make the formatting inside the gridview. Otherwise if you need another formatting then you would have to create another property.

using System;
public class Customer {
private DateTime createDate;
public DateTime CreateDate {
get { return createDate; }
set { createDate = value; }
}
}