【WPF学习】第三十三章 高级命令

<Window x:Class="Commands.TwoDocument"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="TwoDocument" Height="300" Width="300">
    <Window.Resources>
        <CommandBinding  x:Key="binding" Command="ApplicationCommands.Save"
                         Executed="SaveCommand" CanExecute="SaveCommand_CanExecute">
        </CommandBinding>
    </Window.Resources>
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition ></RowDefinition>
            <RowDefinition ></RowDefinition>
        </Grid.RowDefinitions>
        <Menu Grid.Row="0">
            <MenuItem Header="File">
                <MenuItem Command="New"></MenuItem>
                <MenuItem Command="Open"></MenuItem>
                <MenuItem Command="Save"></MenuItem>
                <MenuItem Command="SaveAs"></MenuItem>
                <Separator></Separator>
                <MenuItem Command="Close"></MenuItem>
            </MenuItem>
        </Menu>

        <ToolBarTray Grid.Row="1">
            <ToolBar>
                <Button Command="New">New</Button>
                <Button Command="Open">Open</Button>
                <Button Command="Save">Save</Button>
            </ToolBar>
            <ToolBar>
                <Button Command="Cut">Cut</Button>
                <Button Command="Copy">Copy</Button>
                <Button Command="Paste">Paste</Button>
            </ToolBar>
        </ToolBarTray>
        <TextBox Margin="5" Grid.Row="2" TextWrapping="Wrap" AcceptsReturn="True"
             TextChanged="txt_TextChanged">
            <TextBox.CommandBindings>
                <StaticResource ResourceKey="binding"></StaticResource>
            </TextBox.CommandBindings>
            <!--<TextBox.CommandBindings>
                <CommandBinding Command="ApplicationCommands.Save"
          Executed="SaveCommand" />
            </TextBox.CommandBindings>-->
        </TextBox>
        <TextBox Margin="5" Grid.Row="3" TextWrapping="Wrap" AcceptsReturn="True"
             TextChanged="txt_TextChanged">
            <TextBox.CommandBindings>
                <StaticResource ResourceKey="binding"/>
            </TextBox.CommandBindings>
            <!--<TextBox.CommandBindings>
                <CommandBinding Command="ApplicationCommands.Save"
          Executed="SaveCommand" />
            </TextBox.CommandBindings>-->
        </TextBox>
    </Grid>
</Window>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;

namespace Commands
{
    /// <summary>
    /// TwoDocument.xaml 的交互逻辑
    /// </summary>
    public partial class TwoDocument : Window
    {
        public TwoDocument()
        {
            InitializeComponent();
        }


        private void SaveCommand(object sender, ExecutedRoutedEventArgs e)
        {
            string text = ((TextBox)sender).Text;
            MessageBox.Show("About to save: " + text);
            isDirty[sender] = false;
        }

        private Dictionary<Object, bool> isDirty = new Dictionary<Object, bool>();
        private void txt_TextChanged(object sender, RoutedEventArgs e)
        {
            isDirty[sender] = true;
        }

        private void SaveCommand_CanExecute(object sender, CanExecuteRoutedEventArgs e)
        {
            if (isDirty.ContainsKey(sender) && isDirty[sender] == true)
            {
                e.CanExecute = true;
            }
            else
            {
                e.CanExecute = false;
            }
        }
    }
}

<Window x:Class="Commands.MonitorCommands"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:Commands"
        Title="MonitorCommands" Height="300" Width="329.323" Unloaded="window_Unloaded">
    <Window.CommandBindings>

        <CommandBinding Command="local:MonitorCommands.ApplicationUndo"
                    Executed="ApplicationUndoCommand_Executed"
                    CanExecute="ApplicationUndoCommand_CanExecute"></CommandBinding>
    </Window.CommandBindings>
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"></RowDefinition>
            <RowDefinition></RowDefinition>
            <RowDefinition></RowDefinition>
            <RowDefinition></RowDefinition>
        </Grid.RowDefinitions>


        <ToolBarTray  Grid.Row="0">
            <ToolBar>
                <Button Command="ApplicationCommands.Cut">Cut</Button>
                <Button Command="ApplicationCommands.Copy">Copy</Button>
                <Button Command="ApplicationCommands.Paste">Paste</Button>
                <Button Command="ApplicationCommands.Undo">Undo</Button>
            </ToolBar>
            <ToolBar Margin="0,0,-23,0">
                <Button Command="local:MonitorCommands.ApplicationUndo">Reverse Last Command</Button>
            </ToolBar>
        </ToolBarTray>
        <TextBox Margin="5" Grid.Row="1"
             TextWrapping="Wrap" AcceptsReturn="True">
        </TextBox>
        <TextBox Margin="5" Grid.Row="2"
             TextWrapping="Wrap" AcceptsReturn="True">
        </TextBox>
        <ListBox Grid.Row="3" Name="lstHistory" Margin="5" DisplayMemberPath="CommandName"></ListBox>
    </Grid>
</Window>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;

namespace Commands
{
    /// <summary>
    /// MonitorCommands.xaml 的交互逻辑
    /// </summary>
    public partial class MonitorCommands : Window
    {
        private static RoutedUICommand applicationUndo;
        public static RoutedUICommand ApplicationUndo
        {
            get { return applicationUndo; }
        }

        static MonitorCommands()
        {
            applicationUndo = new RoutedUICommand("ApplicationUndo", "Application Undo", typeof(MonitorCommands));
            
        }
        public MonitorCommands()
        {
            InitializeComponent();
            this.AddHandler(CommandManager.PreviewExecutedEvent,
               new ExecutedRoutedEventHandler(CommandExecuted));
        }

        private void window_Unloaded(object sender, RoutedEventArgs e)
        {
            this.RemoveHandler(CommandManager.PreviewExecutedEvent,
               new ExecutedRoutedEventHandler(CommandExecuted));
        }

        private void CommandExecuted(object sender, ExecutedRoutedEventArgs e)
        {
            // Ignore menu button source.
            if (e.Source is ICommandSource) return;

            // Ignore the ApplicationUndo command.
            if (e.Command == MonitorCommands.ApplicationUndo) return;

            // Could filter for commands you want to add to the stack
            // (for example, not selection events).

            TextBox txt = e.Source as TextBox;
            if (txt != null)
            {
                RoutedCommand cmd = (RoutedCommand)e.Command;

                CommandHistoryItem historyItem = new CommandHistoryItem(
                    cmd.Name, txt, "Text", txt.Text);

                ListBoxItem item = new ListBoxItem();
                item.Content = historyItem;
                lstHistory.Items.Add(historyItem);

                // CommandManager.InvalidateRequerySuggested();
            }
        }

        private void ApplicationUndoCommand_Executed(object sender, RoutedEventArgs e)
        {
            CommandHistoryItem historyItem = (CommandHistoryItem)lstHistory.Items[lstHistory.Items.Count - 1];
            if (historyItem.CanUndo) historyItem.Undo();
            lstHistory.Items.Remove(historyItem);
        }

        private void ApplicationUndoCommand_CanExecute(object sender, CanExecuteRoutedEventArgs e)
        {
            if (lstHistory == null || lstHistory.Items.Count == 0)
                e.CanExecute = false;
            else
                e.CanExecute = true;
        }
    }

    public class CommandHistoryItem
    {
        public string CommandName
        {
            get;
            set;
        }

        public UIElement ElementActedOn
        {
            get;
            set;
        }

        public string PropertyActedOn
        {
            get;
            set;
        }

        public object PreviousState
        {
            get;
            set;
        }

        public CommandHistoryItem(string commandName)
            : this(commandName, null, "", null)
        { }

        public CommandHistoryItem(string commandName, UIElement elementActedOn,
            string propertyActedOn, object previousState)
        {
            CommandName = commandName;
            ElementActedOn = elementActedOn;
            PropertyActedOn = propertyActedOn;
            PreviousState = previousState;
        }
        public bool CanUndo
        {
            get { return (ElementActedOn != null && PropertyActedOn != ""); }
        }

        public void Undo()
        {
            Type elementType = ElementActedOn.GetType();
            PropertyInfo property = elementType.GetProperty(PropertyActedOn);
            property.SetValue(ElementActedOn, PreviousState, null);
        }
    }
}