Two more samples (dotnet#237)

* Two more samples.

* Add readme's.

6.0/Fundamentals/DataBindingDemos/DataBindingDemos.sln

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+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.0.31611.283
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "DataBindingDemos", "DataBindingDemos\DataBindingDemos.csproj", "{76AFC62D-A22C-4057-A411-D5A1E1D068F4}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{76AFC62D-A22C-4057-A411-D5A1E1D068F4}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{76AFC62D-A22C-4057-A411-D5A1E1D068F4}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{76AFC62D-A22C-4057-A411-D5A1E1D068F4}.Debug|Any CPU.Deploy.0 = Debug|Any CPU
+		{76AFC62D-A22C-4057-A411-D5A1E1D068F4}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{76AFC62D-A22C-4057-A411-D5A1E1D068F4}.Release|Any CPU.Build.0 = Release|Any CPU
+		{76AFC62D-A22C-4057-A411-D5A1E1D068F4}.Release|Any CPU.Deploy.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {61F7FB11-1E47-470C-91E2-47F8143E1572}
+	EndGlobalSection
+EndGlobal

6.0/Fundamentals/DataBindingDemos/DataBindingDemos/App.xaml

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+<?xml version = "1.0" encoding = "UTF-8" ?>
+<Application xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             xmlns:local="clr-namespace:DataBindingDemos"
+             x:Class="DataBindingDemos.App">
+    <Application.Resources>
+        <ResourceDictionary>
+            <ResourceDictionary.MergedDictionaries>
+                <ResourceDictionary Source="Resources/Styles/Colors.xaml" />
+                <ResourceDictionary Source="Resources/Styles/Styles.xaml" />
+            </ResourceDictionary.MergedDictionaries>
+
+            <Style TargetType="StackLayout">
+                <Setter Property="Spacing" Value="6" />
+            </Style>
+
+            <Style TargetType="Grid">
+                <Setter Property="RowSpacing" Value="6" />
+                <Setter Property="ColumnSpacing" Value="6" />
+            </Style>
+
+            <x:String x:Key="fallbackImageUrl">https://upload.wikimedia.org/wikipedia/commons/2/20/Point_d_interrogation.jpg</x:String>
+            <x:String x:Key="locationUnknown">Location unknown</x:String>
+            <x:String x:Key="populationUnknown">Population size unknown</x:String>
+            <x:String x:Key="unknown">Unknown</x:String>
+
+        </ResourceDictionary>
+    </Application.Resources>
+</Application>

6.0/Fundamentals/DataBindingDemos/DataBindingDemos/App.xaml.cs

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+namespace DataBindingDemos;
+
+public partial class App : Application
+{
+	public App()
+	{
+		InitializeComponent();
+
+		MainPage = new AppShell();
+	}
+}

6.0/Fundamentals/DataBindingDemos/DataBindingDemos/AppShell.xaml

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+<?xml version="1.0" encoding="UTF-8" ?>
+<Shell
+    x:Class="DataBindingDemos.AppShell"
+    xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+    xmlns:local="clr-namespace:DataBindingDemos"
+    Shell.FlyoutBehavior="Disabled">
+
+    <ShellContent
+        Title="Home"
+        ContentTemplate="{DataTemplate local:MainPage}"
+        Route="MainPage" />
+
+</Shell>

6.0/Fundamentals/DataBindingDemos/DataBindingDemos/AppShell.xaml.cs

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+namespace DataBindingDemos;
+
+public partial class AppShell : Shell
+{
+	public AppShell()
+	{
+		InitializeComponent();
+	}
+}

6.0/Fundamentals/DataBindingDemos/DataBindingDemos/Controls/CardView.cs

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+namespace DataBindingDemos.Controls
+{
+    public class CardView : ContentView
+    {
+        public static readonly BindableProperty CardTitleProperty = BindableProperty.Create(nameof(CardTitle), typeof(string), typeof(CardView), string.Empty);
+        public static readonly BindableProperty CardDescriptionProperty = BindableProperty.Create(nameof(CardDescription), typeof(string), typeof(CardView), string.Empty);
+        public static readonly BindableProperty BorderColorProperty = BindableProperty.Create(nameof(BorderColor), typeof(Color), typeof(CardView), Colors.DarkGray);
+        public static readonly BindableProperty CardColorProperty = BindableProperty.Create(nameof(CardColor), typeof(Color), typeof(CardView), Colors.White);
+        public static readonly BindableProperty IconImageSourceProperty = BindableProperty.Create(nameof(IconImageSource), typeof(ImageSource), typeof(CardView), default(ImageSource));
+        public static readonly BindableProperty IconBackgroundColorProperty = BindableProperty.Create(nameof(IconBackgroundColor), typeof(Color), typeof(CardView), Colors.LightGray);
+
+        public string CardTitle
+        {
+            get => (string)GetValue(CardView.CardTitleProperty);
+            set => SetValue(CardView.CardTitleProperty, value);
+        }
+
+        public string CardDescription
+        {
+            get => (string)GetValue(CardView.CardDescriptionProperty);
+            set => SetValue(CardView.CardDescriptionProperty, value);
+        }
+
+        public Color BorderColor
+        {
+            get => (Color)GetValue(CardView.BorderColorProperty);
+            set => SetValue(CardView.BorderColorProperty, value);
+        }
+
+        public Color CardColor
+        {
+            get => (Color)GetValue(CardView.CardColorProperty);
+            set => SetValue(CardView.CardColorProperty, value);
+        }
+
+        public ImageSource IconImageSource
+        {
+            get => (ImageSource)GetValue(CardView.IconImageSourceProperty);
+            set => SetValue(CardView.IconImageSourceProperty, value);
+        }
+
+        public Color IconBackgroundColor
+        {
+            get => (Color)GetValue(CardView.IconBackgroundColorProperty);
+            set => SetValue(CardView.IconBackgroundColorProperty, value);
+        }
+    }
+}

6.0/Fundamentals/DataBindingDemos/DataBindingDemos/Controls/CardViewExpander.cs

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+namespace DataBindingDemos.Controls
+{
+    public class CardViewExpander : ContentView
+    {
+        public static readonly BindableProperty CardTitleProperty = BindableProperty.Create(nameof(CardTitle), typeof(string), typeof(CardViewExpander), string.Empty);
+        public static readonly BindableProperty CardDescriptionProperty = BindableProperty.Create(nameof(CardDescription), typeof(string), typeof(CardViewExpander), string.Empty);
+        public static readonly BindableProperty BorderColorProperty = BindableProperty.Create(nameof(BorderColor), typeof(Color), typeof(CardViewExpander), Colors.DarkGray);
+        public static readonly BindableProperty CardColorProperty = BindableProperty.Create(nameof(CardColor), typeof(Color), typeof(CardViewExpander), Colors.White);
+        public static readonly BindableProperty IconImageSourceProperty = BindableProperty.Create(nameof(IconImageSource), typeof(ImageSource), typeof(CardViewExpander), default(ImageSource));
+        public static readonly BindableProperty IconBackgroundColorProperty = BindableProperty.Create(nameof(IconBackgroundColor), typeof(Color), typeof(CardViewExpander), Colors.LightGray);
+        public static readonly BindableProperty IsExpandedProperty = BindableProperty.Create(nameof(IsExpanded), typeof(bool), typeof(CardViewExpander), false);
+
+        public string CardTitle
+        {
+            get => (string)GetValue(CardViewExpander.CardTitleProperty);
+            set => SetValue(CardViewExpander.CardTitleProperty, value);
+        }
+
+        public string CardDescription
+        {
+            get => (string)GetValue(CardViewExpander.CardDescriptionProperty);
+            set => SetValue(CardViewExpander.CardDescriptionProperty, value);
+        }
+
+        public Color BorderColor
+        {
+            get => (Color)GetValue(CardViewExpander.BorderColorProperty);
+            set => SetValue(CardViewExpander.BorderColorProperty, value);
+        }
+
+        public Color CardColor
+        {
+            get => (Color)GetValue(CardViewExpander.CardColorProperty);
+            set => SetValue(CardViewExpander.CardColorProperty, value);
+        }
+
+        public ImageSource IconImageSource
+        {
+            get => (ImageSource)GetValue(CardViewExpander.IconImageSourceProperty);
+            set => SetValue(CardViewExpander.IconImageSourceProperty, value);
+        }
+
+        public Color IconBackgroundColor
+        {
+            get => (Color)GetValue(CardViewExpander.IconBackgroundColorProperty);
+            set => SetValue(CardViewExpander.IconBackgroundColorProperty, value);
+        }
+
+        public bool IsExpanded
+        {
+            get => (bool)GetValue(CardViewExpander.IsExpandedProperty);
+            set => SetValue(CardViewExpander.IsExpandedProperty, value);
+        }
+    }
+}

6.0/Fundamentals/DataBindingDemos/DataBindingDemos/Controls/Expander.cs

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+namespace DataBindingDemos
+{
+    // This is a hack until the Expander is present in .NET MAUI Community Toolkit.
+    public class Expander : Grid
+    {
+        public static readonly BindableProperty IsExpandedProperty = BindableProperty.Create(nameof(IsExpanded), typeof(bool), typeof(Expander), false);
+
+        public bool IsExpanded
+        {
+            get => (bool)GetValue(IsExpandedProperty);
+            set => SetValue(IsExpandedProperty, value);
+        }
+    }
+}

6.0/Fundamentals/DataBindingDemos/DataBindingDemos/Controls/Separator.cs

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+namespace DataBindingDemos.Controls
+{
+    public class Separator : BoxView
+    {
+        public Separator()
+        {
+            Color = Colors.Gray;
+            HeightRequest = 2;
+            Opacity = 0.5;
+        }
+    }
+}

6.0/Fundamentals/DataBindingDemos/DataBindingDemos/Converters/AllTrueMultiConverter.cs

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+using System.Globalization;
+
+namespace DataBindingDemos
+{
+    public class AllTrueMultiConverter : IMultiValueConverter
+    {
+        public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
+        {
+            if (values == null || !targetType.IsAssignableFrom(typeof(bool)))
+            {
+                return false;
+                // Alternatively, return BindableProperty.UnsetValue to use the binding FallbackValue
+            }
+
+            foreach (var value in values)
+            {
+                if (!(value is bool b))
+                {
+                    return false;
+                    // Alternatively, return BindableProperty.UnsetValue to use the binding FallbackValue
+                }
+                else if (!b)
+                {
+                    return false;
+                }
+            }
+            return true;
+        }
+
+        public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
+        {
+            if (!(value is bool b) || targetTypes.Any(t => !t.IsAssignableFrom(typeof(bool))))
+            {
+                // Return null to indicate conversion back is not possible
+                return null;
+            }
+
+            if (b)
+            {
+                return targetTypes.Select(t => (object)true).ToArray();
+            }
+            else
+            {
+                // Can't convert back from false because of ambiguity
+                return null;
+            }
+        }
+    }
+}

6.0/Fundamentals/DataBindingDemos/DataBindingDemos/Converters/AnyTrueMultiConverter.cs

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+using System.Globalization;
+
+namespace DataBindingDemos
+{
+    public class AnyTrueMultiConverter : IMultiValueConverter
+    {
+        public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
+        {
+            if (values == null || !targetType.IsAssignableFrom(typeof(bool)))
+            {
+                return false;
+                // Alternatively, return BindableProperty.UnsetValue to use the binding FallbackValue               
+            }
+
+            foreach (var value in values)
+            {
+                if (!(value is bool b))
+                {
+                    return false;
+                    // Alternatively, return BindableProperty.UnsetValue to use the binding FallbackValue
+                }
+                else if (b)
+                {
+                    return true;
+                }                    
+            }
+            return false;
+        }
+
+        public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
+        {
+            if (!(value is bool b) || targetTypes.Any(t => !t.IsAssignableFrom(typeof(bool))))
+            {
+                // Return null to indicate conversion back is not possible
+                return null;
+            }
+
+            if (!b)
+            {
+                return targetTypes.Select(t => (object)false).ToArray();
+            }
+            else
+            {
+                // Can't convert back from true because of ambiguity
+                return null;
+            }
+        }
+    }
+}

6.0/Fundamentals/DataBindingDemos/DataBindingDemos/Converters/BoolToObjectConverter.cs

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+using System.Globalization;
+
+namespace DataBindingDemos
+{
+    public class BoolToObjectConverter<T> : IValueConverter
+    {
+        public T TrueObject { set; get; }
+
+        public T FalseObject { set; get; }
+
+        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            return (bool)value ? TrueObject : FalseObject;
+        }
+
+        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            return ((T)value).Equals(TrueObject);
+        }
+    }
+}

6.0/Fundamentals/DataBindingDemos/DataBindingDemos/Converters/FloatToIntConverter.cs

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+using System.Globalization;
+
+namespace DataBindingDemos
+{
+    public class FloatToIntConverter : IValueConverter
+    {
+        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            return (int)Math.Round((float)value * GetParameter(parameter));
+        }
+
+        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            return (int)value / GetParameter(parameter);
+        }
+
+        double GetParameter(object parameter)
+        {
+            if (parameter is float)
+                return (float)parameter;
+
+            else if (parameter is int)
+                return (int)parameter;
+
+            else if (parameter is string)
+                return float.Parse((string)parameter);
+
+            return 1;
+        }
+    }
+}

6.0/Fundamentals/DataBindingDemos/DataBindingDemos/Converters/IntToBoolConverter.cs

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+using System.Globalization;
+
+namespace DataBindingDemos
+{
+    public class IntToBoolConverter : IValueConverter
+    {
+        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            return (int)value != 0;
+        }
+
+        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            return (bool)value ? 1 : 0;
+        }
+    }
+}