WPF コマンド簡易例

コマンドの実装例をメモします。

<Window x:Class="WpfApplication5.CommandTest"
        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:local="clr-namespace:WpfApplication5"
        mc:Ignorable="d"
        Title="CommandTest" Height="150" Width="300">
    <Grid>
        <TextBox x:Name="textBox"
                 HorizontalAlignment="Left"
                 Height="23"
                 Text="{Binding MyText}"
                 Width="120"/>
        <Button x:Name="button"
                Content="Clear Text"
                Command="{Binding ClearText}"
                CommandParameter="{Binding ElementName=textBox}"
                HorizontalAlignment="Left"
                Width="75"
                Margin="125,0,0,0" Height="23"/>
    </Grid>
</Window>

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;

namespace WpfApplication5
{
    public partial class CommandTest : Window
    {
        public CommandTest()
        {
            InitializeComponent();

            MyData data = new MyData();
            data.MyText = "123 test";

            this.DataContext = data;
        }
    }

    public class MyData : NotificationObject
    {
        private string _MyText;
        public string MyText
        {
            get
            {
                return _MyText;
            }
            set
            {
                this._MyText = value;
                this.OnPropertyChanged();
            }
        }

        private ClearTextCommand _ClearText;
        public ClearTextCommand ClearText {
            get{
                if(_ClearText == null)
                {
                    _ClearText = new ClearTextCommand();
                }
                return _ClearText;
            }
        }
    }

    public class ClearTextCommand : ICommand
    {
        public event EventHandler CanExecuteChanged;

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

        public void Execute(object parameter)
        {
            TextBox textBox = parameter as TextBox;
            textBox?.Clear();
        }
    }
}