Snap to model or ViewModel

Question

I created a project using the MVVM template (or so I thought;)). To simplify my case:

Model

public class Model {
    public string Name { get; set; }
    public bool IsDefective { get; set; }
}

ViewModel - extends MvvmLight ViewModelBase:

public class ViewModel : ViewModelBase {
    private ObservableCollection<Model> models;
    public ObservableCollection<Model> Models {
        get {
            if (_models== null) {
                _models= new ObservableCollection<Models>();
            }

            return _models;
        }
        set {
            RaisePropertyChanged("Models");

            _models= value;
        }
    }
}

View . I am showing a list of text fields:

<TextBlock Text="{Binding Name}">
    <TextBlock.Style>
        <Style TargetType="{x:Type TextBlock}">
            <Style.Triggers>
                <DataTrigger Binding="{Binding Path=.IsDefective}" Value="True">
                    <Setter Property="Foreground" Value="Red" />
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </TextBlock.Style>
</TextBlock>

: Model IsDefective, INotifyPropertyChanged, . " mvvm"? , SO, , , , , : MVVM - PropertyChanged ViewModel?. , , , mvvm, - . , ?

Answer 1

, , . , , , SOLID-. , , - , , POCO ( CLR) -.

:

:

ViewModelBase.cs

"" ViewModelBase galasoft, ( )

namespace WPFPlayground.ViewModel
{
    public abstract class ViewModelBase : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;

        public void SetValue<T>(ref T property, T value, [CallerMemberName] string propertyName = null)
        {
            if (property != null)
            {
                if (property.Equals(value)) return;
            }

            OnPropertyChanged(propertyName);
            property = value;
        }

        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
        {
            var handler = PropertyChanged;
            if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

DefectiveToBackgroundColorConverter.cs

, (. ):

using System;
using System.Globalization;
using System.Windows.Data;
using System.Windows.Media;

namespace WPFPlayground
{
    public class DefectiveToBackgroundColorConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            if (System.Convert.ToBoolean(value))
            {
                return new SolidColorBrush(Colors.Red);
            }
            return new SolidColorBrush(Colors.White);
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            return Binding.DoNothing;
        }
    }
}

Model-first:

ProductModel.cs

POCO DTO

namespace WPFPlayground.Model
{
    public class ProductModel
    {
        public string Name { get; set; }
        public bool IsDefective { get; set; }
    }
}

ProductViewModel.cs

setvalue notifypropertychanged.

namespace WPFPlayground.ViewModel
{
    public class ProductViewModel : ViewModelBase
    {
        private string _name;
        private bool _isDefective;

        public bool IsDefective
        {
            get { return _isDefective; }
            set { SetValue(ref _isDefective, value); }
        }

        public string Name
        {
            get { return _name; }
            set { SetValue(ref _name, value); }
        }
    }
}

, . , , .

, , :

ProductView.xaml

<UserControl x:Class="WPFPlayground.View.ProductView"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             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:wpfPlayground="clr-namespace:WPFPlayground"
             mc:Ignorable="d" 
             d:DataContext="{d:DesignInstance wpfPlayground:DesignProductViewModel, IsDesignTimeCreatable=True}">
    <UserControl.Resources>
        <wpfPlayground:DefectiveToBackgroundColorConverter x:Key="DefectiveToBackgroundColorConverter" />
    </UserControl.Resources>
    <Viewbox>
        <Border Width="500" Background="{Binding IsDefective, Converter={StaticResource DefectiveToBackgroundColorConverter}}">
            <TextBlock Text="{Binding Name}" FontSize="40" TextWrapping="Wrap" VerticalAlignment="Center" HorizontalAlignment="Center" />
        </Border>
    </Viewbox>
</UserControl>

, XAML :

DesignProductViewModel.cs

, !

using WPFPlayground.ViewModel;

namespace WPFPlayground
{
    public class DesignProductViewModel : ProductViewModel
    {
        public DesignProductViewModel()
        {
            Name = "This is my product";
            IsDefective = true;
        }
    }
}

:

MainWindow.xaml

Itemscontrol err day

<Window x:Class="WPFPlayground.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:viewModel="clr-namespace:WPFPlayground.ViewModel"
        xmlns:view="clr-namespace:WPFPlayground.View"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525" d:DataContext="{d:DesignInstance viewModel:DesignProductsViewModel, IsDesignTimeCreatable=True}">
    <Window.Resources>
        <DataTemplate DataType="{x:Type viewModel:ProductViewModel}">
            <view:ProductView />
        </DataTemplate>
    </Window.Resources>
    <StackPanel>
        <ItemsControl ItemsSource="{Binding Products}">
            <view:ProductView />
        </ItemsControl>
    </StackPanel>
</Window>

DesignProductsViewModel.cs

, , . . , pretteh.

using System;
using System.Collections.ObjectModel;
using System.Linq;

namespace WPFPlayground.ViewModel
{
    public class DesignProductsViewModel : ProductsViewModel
    {
        public DesignProductsViewModel()
        {
            var random = new Random();
            Products = new ObservableCollection<ProductViewModel>(Enumerable.Range(1, 5).Select(i => new ProductViewModel
            {
                Name = String.Format(@"Product {0}", i),
                IsDefective = (random.Next(1, 100) < 50)
            }));
        }
    }
}

Answer 2

, Mvvm - , , .

, , Mvvm, "".

INotifyPropertyChanged. "CRUD".