[C#, WPF] MVVMで簡単なアプリを作成

00_mvvm.md

[C#, WPF] MVVMで簡単なアプリを作成

実行画面

設計図

感想

• INotifyPropertyChangedが面倒．プロパティの変化時に自動的に呼び出してほしい
• ICommandが面倒．ボタンをおしたときに直接メソッドを呼び出させてほしい

MainWindow.xaml

<Window x:Class="MVVMTest.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:vm="clr-namespace:MVVMTest.ViewModel" 
        Title="MainWindow" Height="111" Width="205">
    <Window.DataContext>
        <vm:MainWindowViewModel />
    </Window.DataContext>
    <Grid>
        <Button Command="{Binding PushButtonCommand}"  Content="これを押すと下の数字が1増える" HorizontalAlignment="Left" Margin="10,10,0,0" VerticalAlignment="Top" Width="170"/>
        <TextBox HorizontalAlignment="Left" Margin="10,34,0,0" TextWrapping="Wrap" Text="{Binding Count}" Width="120" Height="23" VerticalAlignment="Top"/>
    </Grid>
</Window>

MainWindow.xaml.cs

using System.Windows;

namespace MVVMTest
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }
    }
}

MainWIndowViewModel.cs

using System.ComponentModel;
using System.Windows.Input;

namespace MVVMTest.ViewModel
{
    public class MainWindowViewModel : INotifyPropertyChanged
    {
        public int Count
        {
            get
            {
                return _count;
            }
            set
            {
                _count = value;
                if (PropertyChanged != null) {
                    PropertyChanged(this, new PropertyChangedEventArgs("Count"));
                }
            }
        }

        public ICommand PushButtonCommand
        {
            get
            {
                if (_pushButtonCommand == null) {
                    _pushButtonCommand = new PushButtonCommand(this);
                }
                return _pushButtonCommand;
            }
        }

        private int _count;

        private ICommand _pushButtonCommand;

        public event PropertyChangedEventHandler PropertyChanged;
    }
}

PushButtonCommand.cs

using System;
using System.Windows.Input;

namespace MVVMTest
{
    class PushButtonCommand : ICommand
    {
        private readonly ViewModel.MainWindowViewModel _viewModel;

        public PushButtonCommand(ViewModel.MainWindowViewModel viewModel)
        {
            _viewModel = viewModel;
        }

        public event EventHandler CanExecuteChanged;

        public bool CanExecute(object parameter)
        {
            return true;
        }

        public void Execute(object parameter)
        {
            _viewModel.Count++;
        }
    }
}