Modified error handling to support ModelProperties with multiple errors to implement nested properties.

ucalc/BillingWindow.xaml

@@ -26,7 +26,8 @@
                        LoadCompleted="OnLandlordFrameLoadCompleted"/>
             </TabItem>
             <TabItem Visibility="Collapsed">
-                <Frame Source="Pages/HousePage.xaml"/>
+                <Frame Source="Pages/HousePage.xaml"
+                       LoadCompleted="OnHouseFrameLoadCompleted"/>
             </TabItem>
             <TabItem Visibility="Collapsed">
                 <Frame Source="Pages/TenantsPage.xaml"/>

ucalc/BillingWindow.xaml.cs

@@ -43,5 +43,11 @@ namespace UCalc
             var page = (LandlordPage) ((Frame) sender).Content;
             page.Model = Model.LandlordModel;
         }
+
+        private void OnHouseFrameLoadCompleted(object sender, NavigationEventArgs e)
+        {
+            var page = (HousePage) ((Frame) sender).Content;
+            page.Model = Model.HouseModel;
+        }
     }
 }

ucalc/Controls/ErrorIcon.xaml

@@ -9,12 +9,13 @@
              Height="16">
 
     <UserControl.Resources>
-        <local:ErrorToVisibilityConverter x:Key="ErrorToVisibilityConverter" />
-        <local:ErrorToInVisibilityConverter x:Key="ErrorToInVisibilityConverter" />
+        <local:ErrorsToVisibilityConverter x:Key="ErrorsToVisibilityConverter" />
+        <local:ErrorsToInVisibilityConverter x:Key="ErrorsToInVisibilityConverter" />
     </UserControl.Resources>
-    <StackPanel ToolTip="{Binding Path=Error, RelativeSource={RelativeSource AncestorType=local:ErrorIcon}}">
+    
+    <StackPanel ToolTip="{Binding Path=ErrorsToolTip, RelativeSource={RelativeSource AncestorType=local:ErrorIcon}}">
         <Viewbox
-            Visibility="{Binding Path=Error, RelativeSource={RelativeSource AncestorType=local:ErrorIcon}, Converter={StaticResource ErrorToInVisibilityConverter}}"
+            Visibility="{Binding Path=Errors, RelativeSource={RelativeSource AncestorType=local:ErrorIcon}, Converter={StaticResource ErrorsToInVisibilityConverter}}"
             Stretch="Uniform">
             <Canvas Width="512" Height="512">
                 <Canvas.RenderTransform>
@@ -31,7 +32,7 @@
         </Viewbox>
 
         <Viewbox
-            Visibility="{Binding Path=Error, RelativeSource={RelativeSource AncestorType=local:ErrorIcon}, Converter={StaticResource ErrorToVisibilityConverter}}"
+            Visibility="{Binding Path=Errors, RelativeSource={RelativeSource AncestorType=local:ErrorIcon}, Converter={StaticResource ErrorsToVisibilityConverter}}"
             Stretch="Uniform">
             <Canvas Width="512" Height="512">
                 <Canvas.RenderTransform>

ucalc/Controls/ErrorIcon.xaml.cs

@@ -1,19 +1,18 @@
 using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Runtime.CompilerServices;
 using System.Windows;
 using System.Windows.Data;
+using ucalc.Annotations;
 
 namespace UCalc.Controls
 {
-    public class ErrorToVisibilityConverter : IValueConverter
+    public class ErrorsToVisibilityConverter : IValueConverter
     {
         public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
         {
-            if (value == null || "".Equals(value))
-            {
-                return Visibility.Collapsed;
-            }
-
-            return Visibility.Visible;
+            return (((ICollection<string>) value)?.Count ?? 0) == 0 ? Visibility.Collapsed : Visibility.Visible;
         }
 
         public object ConvertBack(object value, Type targetType, object parameter,
@@ -23,9 +22,9 @@ namespace UCalc.Controls
         }
     }
 
-    public class ErrorToInVisibilityConverter : IValueConverter
+    public class ErrorsToInVisibilityConverter : IValueConverter
     {
-        private readonly ErrorToVisibilityConverter _converter = new ErrorToVisibilityConverter();
+        private readonly ErrorsToVisibilityConverter _converter = new ErrorsToVisibilityConverter();
 
         public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
         {
@@ -40,16 +39,35 @@ namespace UCalc.Controls
         }
     }
 
-    public partial class ErrorIcon
+    public partial class ErrorIcon : INotifyPropertyChanged
     {
-        public string Error { get; set; }
+        public ICollection<string> Errors { get; set; }
 
-        public static readonly DependencyProperty ErrorProperty = DependencyProperty.Register(
-            "Error", typeof(string), typeof(ErrorIcon), new PropertyMetadata((string) null));
+        public string ErrorsToolTip { get; private set; }
+
+        public static readonly DependencyProperty ErrorsProperty = DependencyProperty.Register(
+            "Errors", typeof(ICollection<string>), typeof(ErrorIcon),
+            new PropertyMetadata(null, OnErrorsChanged));
 
         public ErrorIcon()
         {
             InitializeComponent();
         }
+
+        private static void OnErrorsChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
+        {
+            var self = (ErrorIcon) d;
+            var newErrors = (ICollection<string>) e.NewValue;
+            self.ErrorsToolTip = newErrors.Count > 0 ? string.Join("\n", newErrors) : null;
+            self.OnPropertyChanged("ErrorsToolTip");
+        }
+
+        public event PropertyChangedEventHandler PropertyChanged;
+
+        [NotifyPropertyChangedInvocator]
+        private void OnPropertyChanged([CallerMemberName] string propertyName = null)
+        {
+            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+        }
     }
 }

ucalc/Models/AddressModel.cs

@@ -0,0 +1,39 @@
+using UCalc.Data;
+
+namespace UCalc.Models
+{
+    public class AddressModel : Model
+    {
+        private readonly Address _data;
+        public ModelProperty<string> Street { get; }
+        public ModelProperty<string> HouseNumber { get; }
+        public ModelProperty<string> City { get; }
+        public ModelProperty<string> Postcode { get; }
+
+        public AddressModel(Address data)
+        {
+            _data = data;
+
+            Street = Add(new ModelProperty<string>("Straße", _data.Street, ModelPropertyValidators.IsNotEmpty));
+            HouseNumber =
+                Add(new ModelProperty<string>("Hausnummer", _data.HouseNumber, ModelPropertyValidators.IsNotEmpty));
+            City = Add(new ModelProperty<string>("Stadt", _data.City, ModelPropertyValidators.IsNotEmpty));
+            Postcode = Add(new ModelProperty<string>("PLZ", _data.Postcode, ModelPropertyValidators.IsNotEmpty));
+        }
+
+        public override void Apply()
+        {
+            _data.Street = Street.Value;
+            Street.ResetModified();
+
+            _data.HouseNumber = HouseNumber.Value;
+            HouseNumber.ResetModified();
+
+            _data.City = City.Value;
+            City.ResetModified();
+
+            _data.Postcode = Postcode.Value;
+            Postcode.ResetModified();
+        }
+    }
+}

ucalc/Models/BankAccountModel.cs

@@ -0,0 +1,34 @@
+using UCalc.Data;
+
+namespace UCalc.Models
+{
+    public class BankAccountModel : Model
+    {
+        private readonly BankAccount _data;
+        public ModelProperty<string> Iban { get; }
+        public ModelProperty<string> Bic { get; }
+        public ModelProperty<string> BankName { get; }
+
+        public BankAccountModel(BankAccount data)
+        {
+            _data = data;
+
+            Iban = Add(new ModelProperty<string>("IBAN", _data.Iban, ModelPropertyValidators.IsNotEmpty));
+            Bic = Add(new ModelProperty<string>("BIC", _data.Bic, ModelPropertyValidators.IsNotEmpty));
+            BankName = Add(new ModelProperty<string>("Name der Bank", _data.BankName,
+                ModelPropertyValidators.IsNotEmpty));
+        }
+
+        public override void Apply()
+        {
+            _data.Iban = Iban.Value;
+            Iban.ResetModified();
+
+            _data.Bic = Bic.Value;
+            Bic.ResetModified();
+
+            _data.BankName = BankName.Value;
+            BankName.ResetModified();
+        }
+    }
+}

ucalc/Models/BillingModel.cs

@@ -5,17 +5,18 @@ namespace UCalc.Models
     public class BillingModel : Model
     {
         public LandlordModel LandlordModel { get; }
+        public HouseModel HouseModel { get; }
 
         public BillingModel(Billing billing)
         {
             LandlordModel = new LandlordModel(billing.Landlord);
-
-            Properties = LandlordModel.Properties;
+            HouseModel = new HouseModel(billing.House);
         }
 
         public override void Apply()
         {
             LandlordModel.Apply();
+            HouseModel.Apply();
         }
     }
 }

ucalc/Models/FlatModel.cs

@@ -0,0 +1,40 @@
+using System.Collections.Generic;
+using System.Linq;
+using UCalc.Data;
+
+namespace UCalc.Models
+{
+    public class FlatModel : Model
+    {
+        public Flat Data { get; }
+        public ModelProperty<string> Name { get; }
+        public ModelProperty<string> Size { get; }
+
+        public FlatModel(Flat data, IReadOnlyList<Flat> flats)
+        {
+            Data = data;
+
+            Name = Add(new ModelProperty<string>("Name", Data.Name, (name, value) =>
+            {
+                var error = ModelPropertyValidators.IsNotEmpty(name, value);
+
+                if (error == "" && flats.Any(flat => !ReferenceEquals(flat, Data) && flat.Name == value))
+                {
+                    error = $"{name}: Der Wert \"{value}\" ist nicht eindeutig.";
+                }
+
+                return error;
+            }));
+            Size = Add(new ModelProperty<string>("Größe", Data.Size.ToString(), ModelPropertyValidators.IsNaturalInt));
+        }
+
+        public override void Apply()
+        {
+            Data.Name = Name.Value;
+            Name.ResetModified();
+
+            Data.Size = int.TryParse(Size.Value, out var n) && n > 0 ? n : 0;
+            Size.ResetModified();
+        }
+    }
+}

ucalc/Models/HouseModel.cs

@@ -5,16 +5,53 @@ namespace UCalc.Models
     public class HouseModel : Model
     {
         private readonly House _data;
-        public ModelProperty<string> Street { get; }
-        public ModelProperty<string> HouseNumber { get; }
-        public ModelProperty<string> City { get; }
-        public ModelProperty<string> Postcode { get; }
-
-        // TODO: Flats?
+        public NestedModelProperty<AddressModel> Address { get; }
+        public MultiModelProperty<FlatModel> Flats { get; }
 
         public HouseModel(House data)
         {
             _data = data;
+
+            Address = Add(new NestedModelProperty<AddressModel>(new AddressModel(_data.Address)));
+            Flats = Add(new MultiModelProperty<FlatModel>());
+
+            foreach (var flat in data.Flats)
+            {
+                Flats.Add(new FlatModel(flat, _data.Flats));
+            }
+        }
+
+        public override void Apply()
+        {
+            Address.Model.Apply();
+
+            foreach (var model in Flats.Models)
+            {
+                model.Apply();
+            }
+        }
+
+        public FlatModel AddFlat()
+        {
+            var flat = new Flat {Name = $"Wohnung {_data.Flats.Count + 1}"};
+            _data.Flats.Add(flat);
+
+            var model = new FlatModel(flat, _data.Flats);
+            Flats.Add(model);
+
+            return model;
+        }
+
+        public void RemoveFlat(FlatModel model)
+        {
+            _data.Flats.Remove(model.Data);
+
+            Flats.Remove(model);
+
+            if (model.Errors.Count > 0)
+            {
+                OnPropertyChanged("Errors");
+            }
         }
     }
 }

ucalc/Models/LandlordModel.cs

@@ -9,71 +9,39 @@ namespace UCalc.Models
         public ModelProperty<string> Name { get; }
         public ModelProperty<string> MailAddress { get; }
         public ModelProperty<string> Phone { get; }
-        public ModelProperty<string> Street { get; }
-        public ModelProperty<string> HouseNumber { get; }
-        public ModelProperty<string> City { get; }
-        public ModelProperty<string> Postcode { get; }
-        public ModelProperty<string> Iban { get; }
-        public ModelProperty<string> Bic { get; }
-        public ModelProperty<string> BankName { get; }
+        public NestedModelProperty<AddressModel> Address { get; }
+        public NestedModelProperty<BankAccountModel> BankAccount { get; }
 
         public LandlordModel(Landlord data)
         {
             _data = data;
 
-            Salutation = new ModelProperty<int>(this, (int) _data.Salutation, null);
-            Name = new ModelProperty<string>(this, _data.Name, ModelPropertyValidators.IsNotEmpty);
-            MailAddress = new ModelProperty<string>(this, _data.MailAddress, ModelPropertyValidators.IsNotEmpty);
-            Phone = new ModelProperty<string>(this, _data.Phone, ModelPropertyValidators.IsNotEmpty);
-            Street = new ModelProperty<string>(this, _data.Address.Street, ModelPropertyValidators.IsNotEmpty);
-            HouseNumber =
-                new ModelProperty<string>(this, _data.Address.HouseNumber, ModelPropertyValidators.IsNotEmpty);
-            City = new ModelProperty<string>(this, _data.Address.City, ModelPropertyValidators.IsNotEmpty);
-            Postcode = new ModelProperty<string>(this, _data.Address.Postcode, ModelPropertyValidators.IsNotEmpty);
-            Iban = new ModelProperty<string>(this, _data.BankAccount.Iban, ModelPropertyValidators.IsNotEmpty);
-            Bic = new ModelProperty<string>(this, _data.BankAccount.Bic, ModelPropertyValidators.IsNotEmpty);
-            BankName = new ModelProperty<string>(this, _data.BankAccount.BankName, ModelPropertyValidators.IsNotEmpty);
-
-            Properties = new ModelProperty[]
-                {Salutation, Name, MailAddress, Phone, Street, HouseNumber, City, Postcode, Iban, Bic, BankName};
+            Salutation = Add(new ModelProperty<int>("Anrede", (int) _data.Salutation, null));
+            Name = Add(new ModelProperty<string>("Name", _data.Name, ModelPropertyValidators.IsNotEmpty));
+            MailAddress =
+                Add(new ModelProperty<string>("Email Adresse", _data.MailAddress, ModelPropertyValidators.IsNotEmpty));
+            Phone = Add(new ModelProperty<string>("Telefonnummer", _data.Phone, ModelPropertyValidators.IsNotEmpty));
+            Address = Add(new NestedModelProperty<AddressModel>(new AddressModel(_data.Address)));
+            BankAccount = Add(new NestedModelProperty<BankAccountModel>(new BankAccountModel(_data.BankAccount)));
         }
 
         public override void Apply()
         {
-            base.Apply();
-
             _data.Salutation = (Salutation) Salutation.Value;
-            Salutation.Modified = false;
+            Salutation.ResetModified();
 
             _data.Name = Name.Value;
-            Name.Modified = false;
+            Name.ResetModified();
 
             _data.MailAddress = MailAddress.Value;
-            MailAddress.Modified = false;
+            MailAddress.ResetModified();
 
             _data.Phone = Phone.Value;
-            Phone.Modified = false;
+            Phone.ResetModified();
 
-            _data.Address.Street = Street.Value;
-            Street.Modified = false;
+            Address.Model.Apply();
 
-            _data.Address.HouseNumber = HouseNumber.Value;
-            HouseNumber.Modified = false;
-
-            _data.Address.City = City.Value;
-            City.Modified = false;
-
-            _data.Address.Postcode = Postcode.Value;
-            Postcode.Modified = false;
-
-            _data.BankAccount.Iban = Iban.Value;
-            Iban.Modified = false;
-
-            _data.BankAccount.Bic = Bic.Value;
-            Bic.Modified = false;
-
-            _data.BankAccount.BankName = BankName.Value;
-            BankName.Modified = false;
+            BankAccount.Model.Apply();
         }
     }
 }

ucalc/Models/Model.cs

@@ -1,4 +1,6 @@
 using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.ComponentModel;
 using System.Linq;
 using System.Runtime.CompilerServices;
@@ -6,14 +8,107 @@ using ucalc.Annotations;
 
 namespace UCalc.Models
 {
-    public class ModelProperty : INotifyPropertyChanged
+    public abstract class ModelBaseProperty : INotifyPropertyChanged
     {
-        private readonly Model _model;
-        private object _value;
-        private string _error;
-        private readonly Func<object, string> _validate;
+        protected static readonly List<string> EmptyList = new List<string>();
+        public abstract IReadOnlyCollection<string> Errors { get; }
+        public abstract bool Modified { get; }
 
-        public object Value
+        protected void OnChildPropertyChanged(object sender, PropertyChangedEventArgs args)
+        {
+            if (args.PropertyName == "Errors" || args.PropertyName == "Modified")
+            {
+                OnPropertyChanged(args.PropertyName);
+            }
+        }
+
+        public event PropertyChangedEventHandler PropertyChanged;
+
+        [NotifyPropertyChangedInvocator]
+        protected void OnPropertyChanged([CallerMemberName] string propertyName = null)
+        {
+            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+        }
+    }
+
+    public class NestedModelProperty<T> : ModelBaseProperty where T : Model
+    {
+        public T Model { get; }
+
+        public NestedModelProperty(T model)
+        {
+            Model = model;
+
+            Model.PropertyChanged += OnChildPropertyChanged;
+        }
+
+        public override IReadOnlyCollection<string> Errors => Model.Errors;
+
+        public override bool Modified => Model.Modified;
+    }
+
+    public class MultiModelProperty<T> : ModelBaseProperty where T : Model
+    {
+        private readonly ObservableCollection<T> _models;
+
+        public MultiModelProperty()
+        {
+            _models = new ObservableCollection<T>();
+        }
+
+        public void Add(T model)
+        {
+            _models.Add(model);
+
+            model.PropertyChanged += OnChildPropertyChanged;
+
+            if (model.Errors.Count > 0)
+            {
+                OnPropertyChanged("Errors");
+            }
+        }
+
+        public void Remove(T model)
+        {
+            model.PropertyChanged -= OnChildPropertyChanged;
+
+            _models.Remove(model);
+
+            if (model.Errors.Count > 0)
+            {
+                OnPropertyChanged("Errors");
+            }
+        }
+
+        public IReadOnlyList<T> Models => _models;
+
+        public override IReadOnlyCollection<string> Errors
+        {
+            get
+            {
+                var errors = new List<string>();
+
+                foreach (var model in _models)
+                {
+                    errors.AddRange(model.Errors);
+                }
+
+                return errors;
+            }
+        }
+
+        public override bool Modified => _models.Select(model => model.Modified).Any();
+    }
+
+    public class ModelProperty<T> : ModelBaseProperty
+    {
+        public string Name { get; }
+        private T _value;
+        private readonly List<string> _errors;
+        private readonly Func<string, T, string> _validate;
+        private bool _modified;
+
+        public T Value
         {
             get => _value;
             set
@@ -23,94 +118,115 @@ namespace UCalc.Models
                     return;
                 }
 
-                var oldError = Error;
-                Error = _validate?.Invoke(value);
-                if (oldError == null && Error != null || oldError != null && Error == null)
+                var oldError = _errors[0];
+                _errors[0] = _validate?.Invoke(Name, value) ?? "";
+
+                if (oldError != _errors[0])
                 {
-                    _model.OnPropertyChanged("ErrorCount");
+                    OnPropertyChanged("Errors");
                 }
 
-                Modified = true;
+                if (!_modified)
+                {
+                    OnPropertyChanged("Modified");
+                }
+
+                _modified = true;
                 _value = value;
             }
         }
 
-        public string Error
+        public ModelProperty(string name, T value, Func<string, T, string> validate)
         {
-            get => _error;
-            private set
-            {
-                if (_error == value)
-                {
-                    return;
-                }
-
-                _error = value;
-                OnPropertyChanged();
-            }
-        }
-
-        public bool Modified { get; set; }
-
-        public ModelProperty(Model model, object value, Func<object, string> validate)
-        {
-            _model = model;
+            Name = name;
             _value = value;
-            _error = validate?.Invoke(value);
+            _errors = new List<string> {validate?.Invoke(Name, _value) ?? ""};
             _validate = validate;
+            _modified = false;
         }
 
-        public event PropertyChangedEventHandler PropertyChanged;
+        public override IReadOnlyCollection<string> Errors => _errors[0] != "" ? _errors : EmptyList;
 
-        [NotifyPropertyChangedInvocator]
-        private void OnPropertyChanged([CallerMemberName] string propertyName = null)
-        {
-            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
-        }
-    }
+        public override bool Modified => _modified;
 
-    public class ModelProperty<T> : ModelProperty
-    {
-        public new T Value
-        {
-            get => (T) base.Value;
-            set => base.Value = value;
-        }
-
-        public ModelProperty(Model model, T value, Func<T, string> validate) : base(model, value,
-            validate == null ? (Func<object, string>) null : o => validate((T) o))
+        public void ResetModified()
         {
+            _modified = false;
         }
     }
 
     public static class ModelPropertyValidators
     {
-        public static string IsNotEmpty(string data)
+        public static string IsNotEmpty(string name, string data)
         {
-            return string.IsNullOrEmpty(data) ? "Geben Sie einen Wert ein" : null;
+            return string.IsNullOrEmpty(data) ? $"{name}: Geben Sie einen Wert ein." : "";
+        }
+
+        public static string IsNaturalInt(string name, string data)
+        {
+            return !int.TryParse(data, out var n) || n <= 0
+                ? $"{name}: Der eingegebene Wert ist keine gültige positive Zahl > 0."
+                : "";
         }
     }
 
     public abstract class Model : INotifyPropertyChanged
     {
-        public ModelProperty[] Properties { get; protected set; }
+        private readonly List<ModelBaseProperty> _properties;
 
-        public bool Modified => Properties.Select(property => property.Modified).Any();
-
-        public int ErrorCount => Properties.Select(property => string.IsNullOrEmpty(property.Error) ? 0 : 1).Sum();
-
-        public virtual void Apply()
+        protected Model()
         {
-            if (ErrorCount > 0)
+            _properties = new List<ModelBaseProperty>();
+
+            PropertyChanged += (sender, args) =>
             {
-                throw new InvalidOperationException();
+                if (args.PropertyName == "Errors")
+                {
+                    OnPropertyChanged("ErrorCount");
+                }
+            };
+        }
+
+        protected T Add<T>(T property) where T : ModelBaseProperty
+        {
+            _properties.Add(property);
+
+            property.PropertyChanged += (sender, args) =>
+            {
+                if (args.PropertyName == "Errors" || args.PropertyName == "Modified")
+                {
+                    OnPropertyChanged(args.PropertyName);
+                }
+            };
+
+            return property;
+        }
+
+        public bool Modified => _properties.Select(property => property.Modified).Any();
+
+        public IReadOnlyCollection<string> Errors
+        {
+            get
+            {
+                var errors = new List<string>();
+
+                foreach (var property in _properties)
+                {
+                    errors.AddRange(property.Errors);
+                }
+
+                return errors;
             }
         }
 
+        public int ErrorCount => Errors.Count;
+
+        public abstract void Apply();
+
         public event PropertyChangedEventHandler PropertyChanged;
 
         [NotifyPropertyChangedInvocator]
-        public void OnPropertyChanged([CallerMemberName] string propertyName = null)
+        protected void OnPropertyChanged([CallerMemberName] string propertyName = null)
         {
             PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
         }

ucalc/Pages/HousePage.xaml

@@ -3,7 +3,157 @@
       xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
       xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
       xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
-      xmlns:local="clr-namespace:UCalc.Pages"
+      xmlns:local="clr-namespace:UCalc"
+      xmlns:pages="clr-namespace:UCalc.Pages"
+      xmlns:controls="clr-namespace:UCalc.Controls"
       mc:Ignorable="d">
-    <Grid />
-</Page>
+
+    <ScrollViewer HorizontalScrollBarVisibility="Disabled"
+                  VerticalScrollBarVisibility="Auto">
+        <StackPanel>
+            <controls:SectionHeader Header="Adresse des Hauses" />
+
+            <DockPanel Margin="12, 8, 12, 0">
+                <Label DockPanel.Dock="Left"
+                       Content="Straße:"
+                       Width="200"
+                       Foreground="{x:Static local:Constants.SubMainColor}" />
+
+                <controls:ErrorIcon Margin="12, 0, 0, 0"
+                                    DockPanel.Dock="Right"
+                                    VerticalAlignment="Center"
+                                    Errors="{Binding Path=Model.Address.Model.Street.Errors, RelativeSource={RelativeSource AncestorType=pages:HousePage}}" />
+
+                <TextBox
+                    VerticalAlignment="Center"
+                    MinHeight="22"
+                    Text="{Binding Path=Model.Address.Model.Street.Value, RelativeSource={RelativeSource AncestorType=pages:HousePage}, UpdateSourceTrigger=PropertyChanged}" />
+            </DockPanel>
+
+            <DockPanel Margin="12, 8, 12, 0">
+                <Label DockPanel.Dock="Left"
+                       Content="Hausnummer:"
+                       Width="200"
+                       Foreground="{x:Static local:Constants.SubMainColor}" />
+
+                <controls:ErrorIcon Margin="12, 0, 0, 0"
+                                    DockPanel.Dock="Right"
+                                    VerticalAlignment="Center"
+                                    Errors="{Binding Path=Model.Address.Model.HouseNumber.Errors, RelativeSource={RelativeSource AncestorType=pages:HousePage}}" />
+
+                <TextBox
+                    VerticalAlignment="Center"
+                    MinHeight="22"
+                    Text="{Binding Path=Model.Address.Model.HouseNumber.Value, RelativeSource={RelativeSource AncestorType=pages:HousePage}, UpdateSourceTrigger=PropertyChanged}" />
+            </DockPanel>
+
+            <DockPanel Margin="12, 8, 12, 0">
+                <Label DockPanel.Dock="Left"
+                       Content="Stadt:"
+                       Width="200"
+                       Foreground="{x:Static local:Constants.SubMainColor}" />
+
+                <controls:ErrorIcon Margin="12, 0, 0, 0"
+                                    DockPanel.Dock="Right"
+                                    VerticalAlignment="Center"
+                                    Errors="{Binding Path=Model.Address.Model.City.Errors, RelativeSource={RelativeSource AncestorType=pages:HousePage}}" />
+
+                <TextBox
+                    VerticalAlignment="Center"
+                    MinHeight="22"
+                    Text="{Binding Path=Model.Address.Model.City.Value, RelativeSource={RelativeSource AncestorType=pages:HousePage}, UpdateSourceTrigger=PropertyChanged}" />
+            </DockPanel>
+
+            <DockPanel Margin="12, 8, 12, 0">
+                <Label DockPanel.Dock="Left"
+                       Content="PLZ:"
+                       Width="200"
+                       Foreground="{x:Static local:Constants.SubMainColor}" />
+
+                <controls:ErrorIcon Margin="12, 0, 0, 0"
+                                    DockPanel.Dock="Right"
+                                    VerticalAlignment="Center"
+                                    Errors="{Binding Path=Model.Address.Model.Postcode.Errors, RelativeSource={RelativeSource AncestorType=pages:HousePage}}" />
+
+                <TextBox
+                    VerticalAlignment="Center"
+                    MinHeight="22"
+                    Text="{Binding Path=Model.Address.Model.Postcode.Value, RelativeSource={RelativeSource AncestorType=pages:HousePage}, UpdateSourceTrigger=PropertyChanged}" />
+            </DockPanel>
+
+            <controls:SectionHeader Header="Wohnungen"
+                                    Margin="0, 12, 0, 0" />
+
+            <controls:HighlightButton Margin="12, 0, 12, 8"
+                                      HighlightForeground="{x:Static local:Constants.SubMainColor}"
+                                      HighlightBackground="{x:Static local:Constants.MainColor}"
+                                      Click="OnAddFlatClick">
+                <Viewbox Width="24"
+                         Height="24"
+                         Margin="12, 12, 6, 12"
+                         Stretch="Uniform">
+                    <Canvas Width="512" Height="512">
+                        <Canvas.RenderTransform>
+                            <TranslateTransform X="0" Y="0" />
+                        </Canvas.RenderTransform>
+                        <Path>
+                            <Path.Data>
+                                <PathGeometry
+                                    Figures="M256 8C119 8 8 119 8 256s111 248 248 248 248-111 248-248S393 8 256 8zm144 276c0 6.6-5.4 12-12 12h-92v92c0 6.6-5.4 12-12 12h-56c-6.6 0-12-5.4-12-12v-92h-92c-6.6 0-12-5.4-12-12v-56c0-6.6 5.4-12 12-12h92v-92c0-6.6 5.4-12 12-12h56c6.6 0 12 5.4 12 12v92h92c6.6 0 12 5.4 12 12v56z"
+                                    FillRule="NonZero" />
+                            </Path.Data>
+                        </Path>
+                    </Canvas>
+                </Viewbox>
+
+                <Label Content="Wohnung hinzufügen"
+                       Margin="0, 12, 12, 12" />
+            </controls:HighlightButton>
+
+            <ItemsControl
+                ItemsSource="{Binding Path=Model.Flats.Models, RelativeSource={RelativeSource AncestorType=pages:HousePage}}"
+                Margin="12, 0, 12, 12">
+                <ItemsControl.ItemTemplate>
+                    <DataTemplate>
+                        <DockPanel>
+                            <controls:HighlightButton DockPanel.Dock="Right"
+                                                      HighlightForeground="Red"
+                                                      HighlightBackground="White"
+                                                      Click="OnFlatDeleteClick">
+                                <Viewbox Width="24"
+                                         Height="24"
+                                         Margin="8, 12, 8, 12"
+                                         Stretch="Uniform">
+                                    <Canvas Width="448" Height="512">
+                                        <Canvas.RenderTransform>
+                                            <TranslateTransform X="0" Y="0" />
+                                        </Canvas.RenderTransform>
+                                        <Path>
+                                            <Path.Data>
+                                                <PathGeometry
+                                                    Figures="M32 464a48 48 0 0 0 48 48h288a48 48 0 0 0 48-48V128H32zm272-256a16 16 0 0 1 32 0v224a16 16 0 0 1-32 0zm-96 0a16 16 0 0 1 32 0v224a16 16 0 0 1-32 0zm-96 0a16 16 0 0 1 32 0v224a16 16 0 0 1-32 0zM432 32H312l-9.4-18.7A24 24 0 0 0 281.1 0H166.8a23.72 23.72 0 0 0-21.4 13.3L136 32H16A16 16 0 0 0 0 48v32a16 16 0 0 0 16 16h416a16 16 0 0 0 16-16V48a16 16 0 0 0-16-16z"
+                                                    FillRule="NonZero" />
+                                            </Path.Data>
+                                        </Path>
+                                    </Canvas>
+                                </Viewbox>
+                            </controls:HighlightButton>
+
+                            <controls:HighlightButton HighlightForeground="{x:Static local:Constants.SubMainColor}"
+                                                      HighlightBackground="{x:Static local:Constants.MainColor}">
+
+                                <controls:ErrorIcon Errors="{Binding Errors}"
+                                                    DockPanel.Dock="Left"
+                                                    Margin="12, 12, 8, 12" />
+
+                                <Label Content="{Binding Name.Value}"
+                                       VerticalAlignment="Center" />
+                            </controls:HighlightButton>
+                        </DockPanel>
+                    </DataTemplate>
+                </ItemsControl.ItemTemplate>
+            </ItemsControl>
+        </StackPanel>
+    </ScrollViewer>
+
+</Page>

ucalc/Pages/HousePage.xaml.cs

@@ -1,10 +1,32 @@
-namespace UCalc.Pages
+using System.Windows;
+using UCalc.Controls;
+using UCalc.Models;
+
+namespace UCalc.Pages
 {
     public partial class HousePage
     {
+        public HouseModel Model { get; set; }
+
         public HousePage()
         {
             InitializeComponent();
         }
+
+        private void OnAddFlatClick(object sender, RoutedEventArgs e)
+        {
+            Model.AddFlat();
+        }
+
+        private void OnFlatDeleteClick(object sender, RoutedEventArgs e)
+        {
+            var flatModel = (FlatModel) ((HighlightButton) sender).DataContext;
+
+            if (MessageBox.Show($"Möchten Sie die Wohnung \"{flatModel.Data.Name}\" wirlick löschen?", "Löschen?",
+                MessageBoxButton.YesNo, MessageBoxImage.Question) == MessageBoxResult.Yes)
+            {
+                Model.RemoveFlat(flatModel);
+            }
+        }
     }
 }

ucalc/Pages/LandlordPage.xaml

@@ -6,7 +6,6 @@
       xmlns:local="clr-namespace:UCalc"
       xmlns:pages="clr-namespace:UCalc.Pages"
       xmlns:controls="clr-namespace:UCalc.Controls"
-      xmlns:data="clr-namespace:UCalc.Data"
       mc:Ignorable="d">
 
     <ScrollViewer HorizontalScrollBarVisibility="Disabled"
@@ -19,7 +18,7 @@
                        Content="Anrede:"
                        Width="200"
                        Foreground="{x:Static local:Constants.SubMainColor}" />
-                
+
                 <ComboBox Margin="0, 0, 28, 0" /> <!-- TODO -->
             </DockPanel>
 
@@ -32,7 +31,7 @@
                 <controls:ErrorIcon Margin="12, 0, 0, 0"
                                     DockPanel.Dock="Right"
                                     VerticalAlignment="Center"
-                                    Error="{Binding Path=Model.Name.Error, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}}" />
+                                    Errors="{Binding Path=Model.Name.Errors, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}}" />
 
                 <TextBox
                     VerticalAlignment="Center"
@@ -49,7 +48,7 @@
                 <controls:ErrorIcon Margin="12, 0, 0, 0"
                                     DockPanel.Dock="Right"
                                     VerticalAlignment="Center"
-                                    Error="{Binding Path=Model.Phone.Error, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}}" />
+                                    Errors="{Binding Path=Model.Phone.Errors, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}}" />
 
                 <TextBox
                     VerticalAlignment="Center"
@@ -66,16 +65,16 @@
                 <controls:ErrorIcon Margin="12, 0, 0, 0"
                                     DockPanel.Dock="Right"
                                     VerticalAlignment="Center"
-                                    Error="{Binding Path=Model.MailAddress.Error, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}}" />
+                                    Errors="{Binding Path=Model.MailAddress.Errors, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}}" />
 
                 <TextBox
                     VerticalAlignment="Center"
                     MinHeight="22"
                     Text="{Binding Path=Model.MailAddress.Value, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}, UpdateSourceTrigger=PropertyChanged}" />
             </DockPanel>
-            
+
             <controls:SectionHeader Header="Adresse des Eigentümers"
-                                    Margin="0, 12, 0, 0"/>
+                                    Margin="0, 12, 0, 0" />
 
             <DockPanel Margin="12, 8, 12, 0">
                 <Label DockPanel.Dock="Left"
@@ -86,12 +85,12 @@
                 <controls:ErrorIcon Margin="12, 0, 0, 0"
                                     DockPanel.Dock="Right"
                                     VerticalAlignment="Center"
-                                    Error="{Binding Path=Model.Street.Error, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}}" />
+                                    Errors="{Binding Path=Model.Address.Model.Street.Errors, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}}" />
 
                 <TextBox
                     VerticalAlignment="Center"
                     MinHeight="22"
-                    Text="{Binding Path=Model.Street.Value, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}, UpdateSourceTrigger=PropertyChanged}" />
+                    Text="{Binding Path=Model.Address.Model.Street.Value, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}, UpdateSourceTrigger=PropertyChanged}" />
             </DockPanel>
 
             <DockPanel Margin="12, 8, 12, 0">
@@ -103,12 +102,12 @@
                 <controls:ErrorIcon Margin="12, 0, 0, 0"
                                     DockPanel.Dock="Right"
                                     VerticalAlignment="Center"
-                                    Error="{Binding Path=Model.HouseNumber.Error, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}}" />
+                                    Errors="{Binding Path=Model.Address.Model.HouseNumber.Errors, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}}" />
 
                 <TextBox
                     VerticalAlignment="Center"
                     MinHeight="22"
-                    Text="{Binding Path=Model.HouseNumber.Value, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}, UpdateSourceTrigger=PropertyChanged}" />
+                    Text="{Binding Path=Model.Address.Model.HouseNumber.Value, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}, UpdateSourceTrigger=PropertyChanged}" />
             </DockPanel>
 
             <DockPanel Margin="12, 8, 12, 0">
@@ -120,12 +119,12 @@
                 <controls:ErrorIcon Margin="12, 0, 0, 0"
                                     DockPanel.Dock="Right"
                                     VerticalAlignment="Center"
-                                    Error="{Binding Path=Model.City.Error, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}}" />
+                                    Errors="{Binding Path=Model.Address.Model.City.Errors, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}}" />
 
                 <TextBox
                     VerticalAlignment="Center"
                     MinHeight="22"
-                    Text="{Binding Path=Model.City.Value, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}, UpdateSourceTrigger=PropertyChanged}" />
+                    Text="{Binding Path=Model.Address.Model.City.Value, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}, UpdateSourceTrigger=PropertyChanged}" />
             </DockPanel>
 
             <DockPanel Margin="12, 8, 12, 0">
@@ -137,16 +136,16 @@
                 <controls:ErrorIcon Margin="12, 0, 0, 0"
                                     DockPanel.Dock="Right"
                                     VerticalAlignment="Center"
-                                    Error="{Binding Path=Model.Postcode.Error, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}}" />
+                                    Errors="{Binding Path=Model.Address.Model.Postcode.Errors, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}}" />
 
                 <TextBox
                     VerticalAlignment="Center"
                     MinHeight="22"
-                    Text="{Binding Path=Model.Postcode.Value, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}, UpdateSourceTrigger=PropertyChanged}" />
+                    Text="{Binding Path=Model.Address.Model.Postcode.Value, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}, UpdateSourceTrigger=PropertyChanged}" />
             </DockPanel>
-            
+
             <controls:SectionHeader Header="Bankdaten des Eigentümers"
-                                    Margin="0, 12, 0, 0"/>
+                                    Margin="0, 12, 0, 0" />
 
             <DockPanel Margin="12, 8, 12, 0">
                 <Label DockPanel.Dock="Left"
@@ -157,12 +156,12 @@
                 <controls:ErrorIcon Margin="12, 0, 0, 0"
                                     DockPanel.Dock="Right"
                                     VerticalAlignment="Center"
-                                    Error="{Binding Path=Model.Iban.Error, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}}" />
+                                    Errors="{Binding Path=Model.BankAccount.Model.Iban.Errors, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}}" />
 
                 <TextBox
                     VerticalAlignment="Center"
                     MinHeight="22"
-                    Text="{Binding Path=Model.Iban.Value, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}, UpdateSourceTrigger=PropertyChanged}" />
+                    Text="{Binding Path=Model.BankAccount.Model.Iban.Value, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}, UpdateSourceTrigger=PropertyChanged}" />
             </DockPanel>
 
             <DockPanel Margin="12, 8, 12, 0">
@@ -174,12 +173,12 @@
                 <controls:ErrorIcon Margin="12, 0, 0, 0"
                                     DockPanel.Dock="Right"
                                     VerticalAlignment="Center"
-                                    Error="{Binding Path=Model.Bic.Error, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}}" />
+                                    Errors="{Binding Path=Model.BankAccount.Model.Bic.Errors, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}}" />
 
                 <TextBox
                     VerticalAlignment="Center"
                     MinHeight="22"
-                    Text="{Binding Path=Model.Bic.Value, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}, UpdateSourceTrigger=PropertyChanged}" />
+                    Text="{Binding Path=Model.BankAccount.Model.Bic.Value, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}, UpdateSourceTrigger=PropertyChanged}" />
             </DockPanel>
 
             <DockPanel Margin="12, 8, 12, 12">
@@ -191,12 +190,12 @@
                 <controls:ErrorIcon Margin="12, 0, 0, 0"
                                     DockPanel.Dock="Right"
                                     VerticalAlignment="Center"
-                                    Error="{Binding Path=Model.BankName.Error, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}}" />
+                                    Errors="{Binding Path=Model.BankAccount.Model.BankName.Errors, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}}" />
 
                 <TextBox
                     VerticalAlignment="Center"
                     MinHeight="22"
-                    Text="{Binding Path=Model.BankName.Value, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}, UpdateSourceTrigger=PropertyChanged}" />
+                    Text="{Binding Path=Model.BankAccount.Model.BankName.Value, RelativeSource={RelativeSource AncestorType=pages:LandlordPage}, UpdateSourceTrigger=PropertyChanged}" />
             </DockPanel>
 
         </StackPanel>

ucalc/Pages/SideBar.xaml

@@ -116,8 +116,7 @@
                 </Canvas>
             </Viewbox>
 
-            <controls:ErrorCounter x:Name="LandlordErrorCounter"
-                                   DockPanel.Dock="Right"
+            <controls:ErrorCounter DockPanel.Dock="Right"
                                    Margin="0, 12, 12, 12"
                                    VerticalAlignment="Center"
                                    Model="{Binding Path=Model.LandlordModel, RelativeSource={RelativeSource AncestorType=pages:SideBar}}"/>
@@ -154,6 +153,11 @@
                 </Canvas>
             </Viewbox>
 
+            <controls:ErrorCounter DockPanel.Dock="Right"
+                                   Margin="0, 12, 12, 12"
+                                   VerticalAlignment="Center"
+                                   Model="{Binding Path=Model.HouseModel, RelativeSource={RelativeSource AncestorType=pages:SideBar}}"/>
+
             <Label Content="Haus"
                    Margin="0, 12, 12, 12"
                    VerticalAlignment="Center"