Merge pull request #482 from telerik/Nasko/calendar-header-fix

Set DataContext for the HeaderContent of the Calendar in order to make it easier to preserve the title when new content is set.

Author: APopatanasov

Controls/Input/Input.UWP/Calendar/View/RadCalendar.cs

@@ -2207,87 +2207,87 @@ internal void UpdateNavigationHeaderContent()
                 return;
             }
 
-            if (this.HeaderContent == null)
+            string headerContent = null;
+            switch (this.DisplayMode)
             {
-                string headerContent = null;
-
-                switch (this.DisplayMode)
-                {
-                    case CalendarDisplayMode.MonthView:
-                        headerContent = string.Format(this.currentCulture, this.MonthViewHeaderFormat, this.DisplayDate);
-                        break;
-                    case CalendarDisplayMode.YearView:
-                        headerContent = string.Format(this.currentCulture, this.YearViewHeaderFormat, this.DisplayDate);
-                        break;
-                    case CalendarDisplayMode.DecadeView:
-                        DateTime decadeStart = CalendarMathHelper.GetFirstDateOfDecade(this.DisplayDate);
-                        DateTime decadeEnd = decadeStart.AddYears(9);
+                case CalendarDisplayMode.MonthView:
+                    headerContent = string.Format(this.currentCulture, this.MonthViewHeaderFormat, this.DisplayDate);
+                    break;
+                case CalendarDisplayMode.YearView:
+                    headerContent = string.Format(this.currentCulture, this.YearViewHeaderFormat, this.DisplayDate);
+                    break;
+                case CalendarDisplayMode.DecadeView:
+                    DateTime decadeStart = CalendarMathHelper.GetFirstDateOfDecade(this.DisplayDate);
+                    DateTime decadeEnd = decadeStart.AddYears(9);
 
-                        headerContent = string.Format(this.currentCulture, this.DecadeViewHeaderFormat, decadeStart, decadeEnd);
-                        break;
-                    case CalendarDisplayMode.CenturyView:
-                        DateTime centuryStart = CalendarMathHelper.GetFirstDateOfCentury(this.DisplayDate);
-                        DateTime centuryEnd = centuryStart.AddYears(99);
+                    headerContent = string.Format(this.currentCulture, this.DecadeViewHeaderFormat, decadeStart, decadeEnd);
+                    break;
+                case CalendarDisplayMode.CenturyView:
+                    DateTime centuryStart = CalendarMathHelper.GetFirstDateOfCentury(this.DisplayDate);
+                    DateTime centuryEnd = centuryStart.AddYears(99);
 
-                        headerContent = string.Format(this.currentCulture, this.CenturyViewHeaderFormat, centuryStart, centuryEnd);
-                        break;
-                    case CalendarDisplayMode.MultiDayView:
-                        string headerText = this.MultiDayViewSettings.MultiDayViewHeaderText;
-                        if (string.IsNullOrEmpty(headerText))
+                    headerContent = string.Format(this.currentCulture, this.CenturyViewHeaderFormat, centuryStart, centuryEnd);
+                    break;
+                case CalendarDisplayMode.MultiDayView:
+                    string headerText = this.MultiDayViewSettings.MultiDayViewHeaderText;
+                    if (string.IsNullOrEmpty(headerText))
+                    {
+                        DateTime firstDateOfCurrentWeek = this.DisplayDate;
+                        DateTime lastDayOfWeek;
+                        int visibleDays = this.MultiDayViewSettings.VisibleDays;
+                        if (this.MultiDayViewSettings.WeekendsVisible)
                         {
-                            DateTime firstDateOfCurrentWeek = this.DisplayDate;
-                            DateTime lastDayOfWeek;
-                            int visibleDays = this.MultiDayViewSettings.VisibleDays;
-                            if (this.MultiDayViewSettings.WeekendsVisible)
-                            {
-                                lastDayOfWeek = firstDateOfCurrentWeek.AddDays(visibleDays);
-                            }
-                            else
-                            {
-                                firstDateOfCurrentWeek = CalendarMathHelper.SetFirstAvailableBusinessDay(firstDateOfCurrentWeek, 1);
-                                lastDayOfWeek = CalendarMathHelper.AddBusinessDays(firstDateOfCurrentWeek, visibleDays);
-                            }
+                            lastDayOfWeek = firstDateOfCurrentWeek.AddDays(visibleDays);
+                        }
+                        else
+                        {
+                            firstDateOfCurrentWeek = CalendarMathHelper.SetFirstAvailableBusinessDay(firstDateOfCurrentWeek, 1);
+                            lastDayOfWeek = CalendarMathHelper.AddBusinessDays(firstDateOfCurrentWeek, visibleDays);
+                        }
 
-                            if (visibleDays == 1)
-                            {
-                                string format = "{0:d MMMM yyyy}";
-                                headerContent = string.Format(this.currentCulture, format, firstDateOfCurrentWeek);
-                            }
-                            else
-                            {
-                                string format = firstDateOfCurrentWeek.Year == lastDayOfWeek.Subtract(TimeSpan.FromTicks(1)).Year ?
-                                  (firstDateOfCurrentWeek.Month == lastDayOfWeek.Subtract(TimeSpan.FromTicks(1)).Month ?
-                                  "{0:d } ~ {1:d MMMM yyyy}" :
-                                  "{0:d MMMM} ~ {1:d MMMM yyyy}") :
-                                  "{0:d MMMM yyyy} ~ {1:d MMMM yyyy}";
-
-                                lastDayOfWeek = lastDayOfWeek.Subtract(TimeSpan.FromTicks(1));
-                                if (!this.MultiDayViewSettings.WeekendsVisible)
-                                {
-                                    lastDayOfWeek = CalendarMathHelper.SetFirstAvailableBusinessDay(lastDayOfWeek, -1);
-                                }
-
-                                headerContent = string.Format(this.currentCulture, format, firstDateOfCurrentWeek, lastDayOfWeek);
-                            }
+                        if (visibleDays == 1)
+                        {
+                            string format = "{0:d MMMM yyyy}";
+                            headerContent = string.Format(this.currentCulture, format, firstDateOfCurrentWeek);
                         }
                         else
                         {
-                            headerContent = headerText;
+                            string format = firstDateOfCurrentWeek.Year == lastDayOfWeek.Subtract(TimeSpan.FromTicks(1)).Year ?
+                              (firstDateOfCurrentWeek.Month == lastDayOfWeek.Subtract(TimeSpan.FromTicks(1)).Month ?
+                              "{0:d } ~ {1:d MMMM yyyy}" :
+                              "{0:d MMMM} ~ {1:d MMMM yyyy}") :
+                              "{0:d MMMM yyyy} ~ {1:d MMMM yyyy}";
+
+                            lastDayOfWeek = lastDayOfWeek.Subtract(TimeSpan.FromTicks(1));
+                            if (!this.MultiDayViewSettings.WeekendsVisible)
+                            {
+                                lastDayOfWeek = CalendarMathHelper.SetFirstAvailableBusinessDay(lastDayOfWeek, -1);
+                            }
+
+                            headerContent = string.Format(this.currentCulture, format, firstDateOfCurrentWeek, lastDayOfWeek);
                         }
+                    }
+                    else
+                    {
+                        headerContent = headerText;
+                    }
 
-                        break;
-                }
+                    break;
+            }
 
+            if (this.HeaderContent == null)
+            {
                 this.navigationPanel.HeaderContent = headerContent;
             }
             else
             {
                 this.navigationPanel.HeaderContent = this.HeaderContent;
+                this.navigationPanel.DataContext = headerContent;
             }
 
             this.navigationPanel.HeaderContentTemplate = this.HeaderContentTemplate;
         }
-        
+
         internal void OnCalendarButtonClicked() 
         {
             this.FooterButtonClicked?.Invoke(this, EventArgs.Empty);