Use nameof in properties

src/Avalonia.Controls/DateTimePickers/DatePicker.cs

@@ -17,69 +17,76 @@ namespace Avalonia.Controls
         /// Define the <see cref="DayFormat"/> Property
         /// </summary>
         public static readonly DirectProperty<DatePicker, string> DayFormatProperty =
-            AvaloniaProperty.RegisterDirect<DatePicker, string>("DayFormat",
+            AvaloniaProperty.RegisterDirect<DatePicker, string>(nameof(DayFormat),
                 x => x.DayFormat, (x, v) => x.DayFormat = v);
 
         /// <summary>
         /// Defines the <see cref="DayVisible"/> Property
         /// </summary>
         public static readonly DirectProperty<DatePicker, bool> DayVisibleProperty =
-            AvaloniaProperty.RegisterDirect<DatePicker, bool>("DayVisible",
+            AvaloniaProperty.RegisterDirect<DatePicker, bool>(nameof(DayVisible),
                 x => x.DayVisible, (x, v) => x.DayVisible = v);
 
         /// <summary>
         /// Defines the <see cref="Header"/> Property
         /// </summary>
         public static readonly StyledProperty<object> HeaderProperty =
-            AvaloniaProperty.Register<DatePicker, object>("Header");
+            AvaloniaProperty.Register<DatePicker, object>(nameof(Header));
 
         /// <summary>
         /// Defines the <see cref="HeaderTemplate"/> Property
         /// </summary>
         public static readonly StyledProperty<IDataTemplate> HeaderTemplateProperty =
-            AvaloniaProperty.Register<DatePicker, IDataTemplate>("HeaderTemplate");
+            AvaloniaProperty.Register<DatePicker, IDataTemplate>(nameof(HeaderTemplate));
 
         /// <summary>
         /// Defines the <see cref="MaxYear"/> Property
         /// </summary>
         public static readonly DirectProperty<DatePicker, DateTimeOffset> MaxYearProperty =
-            AvaloniaProperty.RegisterDirect<DatePicker, DateTimeOffset>("MaxYear", x => x.MaxYear, (x, v) => x.MaxYear = v);
+            AvaloniaProperty.RegisterDirect<DatePicker, DateTimeOffset>(nameof(MaxYear), 
+                x => x.MaxYear, (x, v) => x.MaxYear = v);
 
         /// <summary>
         /// Defines the <see cref="MinYear"/> Property
         /// </summary>
         public static readonly DirectProperty<DatePicker, DateTimeOffset> MinYearProperty =
-            AvaloniaProperty.RegisterDirect<DatePicker, DateTimeOffset>("MinYear", x => x.MinYear, (x, v) => x.MinYear = v);
+            AvaloniaProperty.RegisterDirect<DatePicker, DateTimeOffset>(nameof(MinYear), 
+                x => x.MinYear, (x, v) => x.MinYear = v);
 
         /// <summary>
         /// Defines the <see cref="MonthFormat"/> Property
         /// </summary>
         public static readonly DirectProperty<DatePicker, string> MonthFormatProperty =
-            AvaloniaProperty.RegisterDirect<DatePicker, string>("MonthFormat", x => x.MonthFormat, (x, v) => x.MonthFormat = v);
+            AvaloniaProperty.RegisterDirect<DatePicker, string>(nameof(MonthFormat), 
+                x => x.MonthFormat, (x, v) => x.MonthFormat = v);
 
         /// <summary>
         /// Defines the <see cref="MonthVisible"/> Property
         /// </summary>
         public static readonly DirectProperty<DatePicker, bool> MonthVisibleProperty =
-            AvaloniaProperty.RegisterDirect<DatePicker, bool>("MonthVisible", x => x.MonthVisible, (x, v) => x.MonthVisible = v);
+            AvaloniaProperty.RegisterDirect<DatePicker, bool>(nameof(MonthVisible), 
+                x => x.MonthVisible, (x, v) => x.MonthVisible = v);
 
         /// <summary>
         /// Defiens the <see cref="YearFormat"/> Property
         /// </summary>
         public static readonly DirectProperty<DatePicker, string> YearFormatProperty =
-            AvaloniaProperty.RegisterDirect<DatePicker, string>("YearFormat", x => x.YearFormat, (x, v) => x.YearFormat = v);
+            AvaloniaProperty.RegisterDirect<DatePicker, string>(nameof(YearFormat), 
+                x => x.YearFormat, (x, v) => x.YearFormat = v);
 
         /// <summary>
         /// Defines the <see cref="YearVisible"/> Property
         /// </summary>
         public static readonly DirectProperty<DatePicker, bool> YearVisibleProperty =
-            AvaloniaProperty.RegisterDirect<DatePicker, bool>("YearVisible", x => x.YearVisible, (x, v) => x.YearVisible = v);
+            AvaloniaProperty.RegisterDirect<DatePicker, bool>(nameof(YearVisible), 
+                x => x.YearVisible, (x, v) => x.YearVisible = v);
 
         /// <summary>
         /// Defines the <see cref="SelectedDate"/> Property
         /// </summary>
         public static readonly DirectProperty<DatePicker, DateTimeOffset?> SelectedDateProperty =
-            AvaloniaProperty.RegisterDirect<DatePicker, DateTimeOffset?>("SelectedDate", x => x.SelectedDate, (x, v) => x.SelectedDate = v);
+            AvaloniaProperty.RegisterDirect<DatePicker, DateTimeOffset?>(nameof(SelectedDate), 
+                x => x.SelectedDate, (x, v) => x.SelectedDate = v);
 
         //Template Items
         private Button _flyoutButton;
@@ -385,7 +392,7 @@ namespace Avalonia.Controls
             if (_presenter == null)
                 throw new InvalidOperationException("No DatePickerPresenter found");
 
-            _presenter.Date = SelectedDate.HasValue ? SelectedDate.Value : DateTimeOffset.Now;
+            _presenter.Date = SelectedDate ?? DateTimeOffset.Now;
 
             _popup.IsOpen = true;
 

src/Avalonia.Controls/DateTimePickers/DatePickerPresenter.cs

@@ -18,55 +18,64 @@ namespace Avalonia.Controls
         /// Defines the <see cref="Date"/> Property
         /// </summary>
         public static readonly DirectProperty<DatePickerPresenter, DateTimeOffset> DateProperty =
-            AvaloniaProperty.RegisterDirect<DatePickerPresenter, DateTimeOffset>("Date", x => x.Date, (x, v) => x.Date = v);
+            AvaloniaProperty.RegisterDirect<DatePickerPresenter, DateTimeOffset>(nameof(Date), 
+                x => x.Date, (x, v) => x.Date = v);
 
         /// <summary>
         /// Defines the <see cref="DayFormat"/> Property
         /// </summary>
         public static readonly DirectProperty<DatePickerPresenter, string> DayFormatProperty =
-            DatePicker.DayFormatProperty.AddOwner<DatePickerPresenter>(x => x.DayFormat, (x, v) => x.DayFormat = v);
+            DatePicker.DayFormatProperty.AddOwner<DatePickerPresenter>(x => 
+            x.DayFormat, (x, v) => x.DayFormat = v);
 
         /// <summary>
         /// Defines the <see cref="DayVisible"/> Property
         /// </summary>
         public static readonly DirectProperty<DatePickerPresenter, bool> DayVisibleProperty =
-            DatePicker.DayVisibleProperty.AddOwner<DatePickerPresenter>(x => x.DayVisible, (x, v) => x.DayVisible = v);
+            DatePicker.DayVisibleProperty.AddOwner<DatePickerPresenter>(x => 
+            x.DayVisible, (x, v) => x.DayVisible = v);
 
         /// <summary>
         /// Defines the <see cref="MaxYear"/> Property
         /// </summary>
         public static readonly DirectProperty<DatePickerPresenter, DateTimeOffset> MaxYearProperty =
-            DatePicker.MaxYearProperty.AddOwner<DatePickerPresenter>(x => x.MaxYear, (x, v) => x.MaxYear = v);
+            DatePicker.MaxYearProperty.AddOwner<DatePickerPresenter>(x => 
+            x.MaxYear, (x, v) => x.MaxYear = v);
 
         /// <summary>
         /// Defines the <see cref="MinYear"/> Property
         /// </summary>
         public static readonly DirectProperty<DatePickerPresenter, DateTimeOffset> MinYearProperty =
-            DatePicker.MinYearProperty.AddOwner<DatePickerPresenter>(x => x.MinYear, (x, v) => x.MinYear = v);
+            DatePicker.MinYearProperty.AddOwner<DatePickerPresenter>(x => 
+            x.MinYear, (x, v) => x.MinYear = v);
 
         /// <summary>
         /// Defines the <see cref="MonthFormat"/> Property
         /// </summary>
         public static readonly DirectProperty<DatePickerPresenter, string> MonthFormatProperty =
-            DatePicker.MonthFormatProperty.AddOwner<DatePickerPresenter>(x => x.MonthFormat, (x, v) => x.MonthFormat = v);
+            DatePicker.MonthFormatProperty.AddOwner<DatePickerPresenter>(x => 
+            x.MonthFormat, (x, v) => x.MonthFormat = v);
 
         /// <summary>
         /// Defines the <see cref="MonthVisible"/> Property
         /// </summary>
         public static readonly DirectProperty<DatePickerPresenter, bool> MonthVisibleProperty =
-            DatePicker.MonthVisibleProperty.AddOwner<DatePickerPresenter>(x => x.MonthVisible, (x, v) => x.MonthVisible = v);
+            DatePicker.MonthVisibleProperty.AddOwner<DatePickerPresenter>(x => 
+            x.MonthVisible, (x, v) => x.MonthVisible = v);
 
         /// <summary>
         /// Defines the <see cref="YearFormat"/> Property
         /// </summary>
         public static readonly DirectProperty<DatePickerPresenter, string> YearFormatProperty =
-            DatePicker.YearFormatProperty.AddOwner<DatePickerPresenter>(x => x.YearFormat, (x, v) => x.YearFormat = v);
+            DatePicker.YearFormatProperty.AddOwner<DatePickerPresenter>(x => 
+            x.YearFormat, (x, v) => x.YearFormat = v);
 
         /// <summary>
         /// Defines the <see cref="YearVisible"/> Property
         /// </summary>
         public static readonly DirectProperty<DatePickerPresenter, bool> YearVisibleProperty =
-            DatePicker.YearVisibleProperty.AddOwner<DatePickerPresenter>(x => x.YearVisible, (x, v) => x.YearVisible = v);
+            DatePicker.YearVisibleProperty.AddOwner<DatePickerPresenter>(x => 
+            x.YearVisible, (x, v) => x.YearVisible = v);
 
         //Template Items
         private Grid _pickerContainer;

src/Avalonia.Controls/DateTimePickers/DateTimePickerPanel.cs

@@ -22,25 +22,25 @@ namespace Avalonia.Controls.Primitives
         /// Defines the <see cref="ItemHeight"/> property
         /// </summary>
         public static readonly StyledProperty<double> ItemHeightProperty =
-            AvaloniaProperty.Register<DateTimePickerPanel, double>("ItemHeight", 40.0);
+            AvaloniaProperty.Register<DateTimePickerPanel, double>(nameof(ItemHeight), 40.0);
 
         /// <summary>
         /// Defines the <see cref="PanelType"/> property
         /// </summary>
         public static readonly StyledProperty<DateTimePickerPanelType> PanelTypeProperty =
-            AvaloniaProperty.Register<DateTimePickerPanel, DateTimePickerPanelType>("PanelType");
+            AvaloniaProperty.Register<DateTimePickerPanel, DateTimePickerPanelType>(nameof(PanelType));
 
         /// <summary>
         /// Defines the <see cref="ItemFormat"/> property
         /// </summary>
         public static readonly StyledProperty<string> ItemFormatProperty =
-            AvaloniaProperty.Register<DateTimePickerPanel, string>("ItemFormat", "yyyy");
+            AvaloniaProperty.Register<DateTimePickerPanel, string>(nameof(ItemFormat), "yyyy");
 
         /// <summary>
         /// Defines the <see cref="ShouldLoop"/> property
         /// </summary>
         public static readonly StyledProperty<bool> ShouldLoopProperty =
-            AvaloniaProperty.Register<DateTimePickerPanel, bool>("ShouldLoop");
+            AvaloniaProperty.Register<DateTimePickerPanel, bool>(nameof(ShouldLoop));
 
         //Backing fields for properties
         private int _minimumValue = 1;

src/Avalonia.Controls/DateTimePickers/TimePicker.cs

@@ -15,33 +15,34 @@ namespace Avalonia.Controls
         /// Defines the <see cref="MinuteIncrement"/> property
         /// </summary>
         public static readonly DirectProperty<TimePicker, int> MinuteIncrementProperty =
-            AvaloniaProperty.RegisterDirect<TimePicker, int>("MinuteIncrement", x => x.MinuteIncrement,
-                (x, v) => x.MinuteIncrement = v);
+            AvaloniaProperty.RegisterDirect<TimePicker, int>(nameof(MinuteIncrement), 
+                x => x.MinuteIncrement, (x, v) => x.MinuteIncrement = v);
 
         /// <summary>
         /// Defines the <see cref="Header"/> property
         /// </summary>
         public static readonly StyledProperty<object> HeaderProperty =
-            AvaloniaProperty.Register<DatePicker, object>("Header");
+            AvaloniaProperty.Register<DatePicker, object>(nameof(Header));
 
         /// <summary>
         /// Defines the <see cref="HeaderTemplate"/> property
         /// </summary>
         public static readonly StyledProperty<IDataTemplate> HeaderTemplateProperty =
-            AvaloniaProperty.Register<DatePicker, IDataTemplate>("HeaderTemplate");
+            AvaloniaProperty.Register<DatePicker, IDataTemplate>(nameof(HeaderTemplate));
 
         /// <summary>
         /// Defines the <see cref="ClockIdentifier"/> property
         /// </summary>
         public static readonly DirectProperty<TimePicker, string> ClockIdentifierProperty =
-           AvaloniaProperty.RegisterDirect<TimePicker, string>("ClockIdentifier", x => x.ClockIdentifier,
-               (x, v) => x.ClockIdentifier = v);
+           AvaloniaProperty.RegisterDirect<TimePicker, string>(nameof(ClockIdentifier), 
+               x => x.ClockIdentifier, (x, v) => x.ClockIdentifier = v);
 
         /// <summary>
         /// Defines the <see cref="SelectedTime"/> property
         /// </summary>
         public static readonly DirectProperty<TimePicker, TimeSpan?> SelectedTimeProperty =
-            AvaloniaProperty.RegisterDirect<TimePicker, TimeSpan?>("Time", x => x.SelectedTime, (x, v) => x.SelectedTime = v);
+            AvaloniaProperty.RegisterDirect<TimePicker, TimeSpan?>(nameof(SelectedTime), 
+                x => x.SelectedTime, (x, v) => x.SelectedTime = v);
 
         //Template Items
         private TimePickerPresenter _presenter;
@@ -230,8 +231,6 @@ namespace Avalonia.Controls
             {
                 var newTime = SelectedTime.Value;
 
-                bool clock12 = ClockIdentifier == "12HourClock";
-
                 if (ClockIdentifier == "12HourClock")
                 {
                     var hr = newTime.Hours;
@@ -265,7 +264,7 @@ namespace Avalonia.Controls
 
         private void OnFlyoutButtonClicked(object sender, Avalonia.Interactivity.RoutedEventArgs e)
         {
-            _presenter.Time = SelectedTime.HasValue ? SelectedTime.Value : DateTime.Now.TimeOfDay;
+            _presenter.Time = SelectedTime ?? DateTime.Now.TimeOfDay;
 
             _popup.IsOpen = true;
 

src/Avalonia.Controls/DateTimePickers/TimePickerPresenter.cs

@@ -6,8 +6,6 @@ using System;
 
 namespace Avalonia.Controls
 {
-    //Combines TimePickerFlyout & TimePickerFlyoutPicker from WinUI
-
     /// <summary>
     /// Defines the presenter used for selecting a time. Intended for use with
     /// <see cref="TimePicker"/> but can be used independently
@@ -32,7 +30,7 @@ namespace Avalonia.Controls
         /// Defines the <see cref="Time"/> property
         /// </summary>
         public static readonly DirectProperty<TimePickerPresenter, TimeSpan> TimeProperty =
-            AvaloniaProperty.RegisterDirect<TimePickerPresenter, TimeSpan>("Time",
+            AvaloniaProperty.RegisterDirect<TimePickerPresenter, TimeSpan>(nameof(Time),
                 x => x.Time, (x, v) => x.Time = v);
 
         public TimePickerPresenter()
@@ -100,7 +98,6 @@ namespace Avalonia.Controls
             get => _Time;
             set
             {
-                var old = _Time;
                 SetAndRaise(TimeProperty, ref _Time, value);
                 InitPicker();
             }