Add default implementation of calendar days with events to XCalendar.Core

Author: ME-MarvinE

XCalendar.Core/Interfaces/ICalendar.cs

@@ -1,13 +1,24 @@
 using System;
-using System.Collections.ObjectModel;
 using System.ComponentModel;
 using XCalendar.Core.Collections;
 using XCalendar.Core.Enums;
 using XCalendar.Core.Models;
 
 namespace XCalendar.Core.Interfaces
 {
-    public interface ICalendar<T> : INotifyPropertyChanged where T : ICalendarDay, new()
+    /// <summary>
+    /// An interface representing a calendar.
+    /// </summary>
+    /// <typeparam name="T">A model implementing <see cref="ICalendarDay{TEvent}"/> to be used to represent each day in a page.</typeparam>
+    public interface ICalendar<T> : ICalendar<T, IEvent> where T : ICalendarDay<IEvent>, new()
+    {
+    }
+    /// <summary>
+    /// An interface representing a calendar.
+    /// </summary>
+    /// <typeparam name="T">A model implementing <see cref="ICalendarDay{TEvent}"/> to be used to represent each day in a page.</typeparam>
+    /// <typeparam name="TEvent">A model implementing <see cref="IEvent"/> to be used to represent calendar events.</typeparam>
+    public interface ICalendar<T, TEvent> : INotifyPropertyChanged where T : ICalendarDay<TEvent>, new() where TEvent : IEvent
     {
         #region Properties
         ObservableRangeCollection<T> Days { get; }

XCalendar.Core/Interfaces/ICalendarDay.cs

@@ -1,14 +1,19 @@
 using System;
 using System.ComponentModel;
+using XCalendar.Core.Collections;
 
 namespace XCalendar.Core.Interfaces
 {
-    public interface ICalendarDay : INotifyPropertyChanged
+    public interface ICalendarDay : ICalendarDay<IEvent>
+    {
+    }
+    public interface ICalendarDay<TEvent> : INotifyPropertyChanged where TEvent : IEvent
     {
         DateTime DateTime { get; set; }
         bool IsSelected { get; set; }
         bool IsCurrentMonth { get; set; }
         bool IsToday { get; set; }
         bool IsInvalid { get; set; }
+        ObservableRangeCollection<TEvent> Events { get; set; }
     }
 }

XCalendar.Maui/Interfaces/IEvent.cs XCalendar.Core/Interfaces/IEvent.cs

@@ -1,10 +1,11 @@
-namespace XCalendar.Maui.Interfaces
+using System;
+
+namespace XCalendar.Core.Interfaces
 {
     public interface IEvent
     {
         string Title { get; set; }
         string Description { get; set; }
         DateTime DateTime { get; set; }
-        Color Color { get; set; }
     }
 }

XCalendar.Core/Models/Calendar.cs

@@ -16,14 +16,22 @@ namespace XCalendar.Core.Models
     /// <summary>
     /// A class representing a calendar.
     /// </summary>
-    public class Calendar : Calendar<CalendarDay>
+    public class Calendar : Calendar<CalendarDay, Event>
     {
     }
     /// <summary>
     /// A class representing a calendar.
     /// </summary>
-    /// <typeparam name="T">A model implementing <see cref="ICalendarDay"/> to be used to represent each day in a page.</typeparam>
-    public class Calendar<T> : ICalendar<T> where T : ICalendarDay, new()
+    /// <typeparam name="T">A model implementing <see cref="ICalendarDay{TEvent}"/> to be used to represent each day in a page.</typeparam>
+    public class Calendar<T> : Calendar<T, Event> where T : ICalendarDay<Event>, new()
+    {
+    }
+    /// <summary>
+    /// A class representing a calendar.
+    /// </summary>
+    /// <typeparam name="T">A model implementing <see cref="ICalendarDay{TEvent}"/> to be used to represent each day in a page.</typeparam>
+    /// <typeparam name="TEvent">A model implementing <see cref="IEvent"/> to be used to represent calendar events.</typeparam>
+    public class Calendar<T, TEvent> : ICalendar<T, TEvent> where T : ICalendarDay<TEvent>, new() where TEvent : IEvent
     {
         #region Fields
         protected static readonly ReadOnlyCollection<DayOfWeek> DaysOfWeek = DayOfWeekExtensions.DaysOfWeek;
@@ -46,6 +54,7 @@ public class Calendar : Calendar<CalendarDay>
         private DateTime? _rangeSelectionStart;
         private DateTime? _rangeSelectionEnd;
         private SelectionType _selectionType = SelectionType.None;
+        private ObservableRangeCollection<TEvent> _events = new ObservableRangeCollection<TEvent>();
         #endregion
 
         #region Properties
@@ -438,6 +447,31 @@ public SelectionType SelectionType
                 }
             }
         }
+        public ObservableRangeCollection<TEvent> Events
+        {
+            get
+            {
+                return _events;
+            }
+            set
+            {
+                if (_events != value)
+                {
+                    if (_events != null)
+                    {
+                        _events.CollectionChanged -= Events_CollectionChanged;
+                    }
+
+                    if (value != null)
+                    {
+                        value.CollectionChanged += Events_CollectionChanged;
+                    }
+
+                    _events = value;
+                    OnPropertyChanged();
+                }
+            }
+        }
         #endregion
 
         #region Events
@@ -472,6 +506,8 @@ public Calendar()
                 SelectedDates.CollectionChanged += SelectedDates_CollectionChanged;
             }
 
+            Events.CollectionChanged += Events_CollectionChanged;
+
             //Not needed because days are updated in previous lines of code.
             UpdateDays(NavigatedDate);
         }
@@ -686,6 +722,7 @@ public virtual void UpdateDay(T day, DateTime newDateTime)
             day.IsToday = IsDateTimeToday(day.DateTime);
             day.IsSelected = IsDateTimeSelected(day.DateTime);
             day.IsInvalid = IsDateTimeInvalid(day.DateTime);
+            UpdateDayEvents(day);
         }
         /// <summary>
         /// Updates the dates displayed on the calendar.
@@ -764,6 +801,33 @@ public virtual void UpdateDays(DateTime navigationDate)
 
             OnDaysUpdated();
         }
+        public virtual void UpdateDayEvents(T day)
+        {
+            //It is known that the only thing that the events of the day depend on is the DateTime of the day, and that all events will have the same date.
+            //So, only update the events if the existing ones' DateTime does not match the day's DateTime.
+            //If the day has no events, there is no way to tell if it's because the day hasn't been updated before or if there are no events with that date, so update it either way.
+            if (day.Events.Count > 0 && day.DateTime.Date == day.Events[0].DateTime.Date)
+            {
+                return;
+            }
+
+            IEnumerable<TEvent> events = Events.Where(x => x.DateTime.Date == day.DateTime.Date);
+
+            //No use in replacing the collection if the source and target are both empty.
+            if (day.Events.Count == 0 && !events.Any())
+            {
+                return;
+            }
+
+            //SequenceEqual could be omitted to improve performance but in the vast majority of cases there won't even be more than 5 events in one day, so impact on performance should be negligible
+            //compared to always changing the collection and updating the binding.
+            if (day.Events.SequenceEqual(events))
+            {
+                return;
+            }
+
+            day.Events.ReplaceRange(events);
+        }
         /// <summary>
         /// Navigates the calendar by the specified <see cref="TimeSpan"/> using the navigation rule properties set in the calendar (<see cref="NavigationLowerBound"/>, <see cref="NavigationUpperBound"/> <see cref="NavigationLoopMode"/>).
         /// </summary>
@@ -968,6 +1032,10 @@ private int CoerceRows(int value)
         {
             return AutoRows ? GetMonthRows(NavigatedDate, AutoRowsIsConsistent, StartOfWeek) : value;
         }
+        private void Events_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
+        {
+            UpdateDays(NavigatedDate);
+        }
         protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
         {
             PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));

XCalendar.Core/Models/CalendarDay.cs

@@ -1,18 +1,24 @@
 using System;
 using System.ComponentModel;
 using System.Runtime.CompilerServices;
+using XCalendar.Core.Collections;
 using XCalendar.Core.Interfaces;
 
 namespace XCalendar.Core.Models
 {
-    public class CalendarDay : ICalendarDay
+    public class CalendarDay : CalendarDay<Event>
+    { 
+    }
+
+    public class CalendarDay<TEvent> : ICalendarDay<TEvent> where TEvent : IEvent
     {
         #region Fields
         private DateTime _dateTime = DateTime.Today;
         private bool _isSelected;
         private bool _isCurrentMonth;
         private bool _isToday;
         private bool _isInvalid;
+        private ObservableRangeCollection<TEvent> _events = new ObservableRangeCollection<TEvent>();
         #endregion
 
         #region Properties
@@ -91,6 +97,21 @@ public bool IsInvalid
                 }
             }
         }
+        public ObservableRangeCollection<TEvent> Events
+        {
+            get
+            {
+                return _events;
+            }
+            set
+            {
+                if (_events != value)
+                {
+                    _events = value;
+                    OnPropertyChanged();
+                }
+            }
+        }
         #endregion
 
         #region Events

XCalendar.Forms/Models/Event.cs XCalendar.Core/Models/Event.cs

@@ -1,18 +1,16 @@
 using System;
 using System.ComponentModel;
 using System.Runtime.CompilerServices;
-using Xamarin.Forms;
-using XCalendar.Forms.Interfaces;
+using XCalendar.Core.Interfaces;
 
-namespace XCalendar.Forms.Models
+namespace XCalendar.Core.Models
 {
     public class Event : IEvent, INotifyPropertyChanged
     {
         #region Fields
         private string _title;
         private string _description;
         private DateTime _dateTime = DateTime.Today;
-        private Color _color;
         #endregion
 
         #region Properties
@@ -31,7 +29,8 @@ public string Title
                 }
             }
         }
-        public string Description {
+        public string Description
+        {
             get
             {
                 return _description;
@@ -60,22 +59,6 @@ public DateTime DateTime
                 }
             }
         }
-        public Color Color
-        {
-            get
-            {
-                return _color;
-            }
-            set
-            {
-                if (_color != value)
-                {
-                    _color = value;
-                    OnPropertyChanged();
-                }
-            }
-        }
-
         #endregion
 
         #region Events

XCalendar.Forms/Interfaces/IComplexCalendarDay.cs

@@ -0,0 +1,30 @@
+using Xamarin.Forms;
+using XCalendar.Core.Models;
+
+namespace XCalendar.Forms.Models
+{
+    public class ColoredEvent : Event
+    {
+        #region Fields
+        private Color _color;
+        #endregion
+
+        #region Properties
+        public Color Color
+        {
+            get
+            {
+                return _color;
+            }
+            set
+            {
+                if (_color != value)
+                {
+                    _color = value;
+                    OnPropertyChanged();
+                }
+            }
+        }
+        #endregion
+    }
+}