回答編集履歴

  > あるコレクションのメソッドから他のコレクションの値を変更する事ってできないですよね？

 

  `ChangeParameter`のところの話だと思いますが、表示・非表示を引数に全員回せばいいでしょう。

  ClickMenu = new(x =>

  {

  foreach (var m in MenuModels)

  m.ChangeParameter(x == m);

  });

  ```

 

  ---

 

  とりあえず提示コードを動かすなら、こんな感じでしょうか？

  <Window

  x:Class="Questions329889.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:local="clr-namespace:Questions329889" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

  Title="MainWindow" Width="23cm" Height="14.2cm"

  MinWidth="13cm" MinHeight="14.2cm" mc:Ignorable="d">

  <Window.DataContext>

  <local:MainViewModel />

  </Window.DataContext>

  <Window.Resources>

  <local:String2BrushConverter x:Key="String2BrushConverter" />

  </Window.Resources>

  <Grid>

  <Grid.ColumnDefinitions>

  <ColumnDefinition Width="2cm" />

  <ColumnDefinition MinWidth="21" />

  </Grid.ColumnDefinitions>

 

  <Grid Grid.Column="1" Visibility="{Binding MenuModels[0].Visibility}">

  Text="{Binding MenuModels[0].Content}" />

 

  <ItemsControl x:Name="MyItems" ItemsSource="{Binding MenuModels}">

  <ItemsControl.ItemTemplate>

  <DataTemplate>

  <Grid Margin="15,15,0,0" Visibility="{Binding HomeMenuVisibility}">

  <Border Background="#efebe9" CornerRadius="10" />

  <Button

  Width="350" Height="160" Background="{x:Null}"

  BorderThickness="0" Command="{Binding ElementName=MyItems, Path=DataContext.ClickMenu}" CommandParameter="{Binding}">

  <StackPanel

  Width="330" Height="140" Margin="10">

  <StackPanel Orientation="Horizontal">

  <TextBlock

  Margin="10,0,10,0" HorizontalAlignment="Center" VerticalAlignment="Center"

  FontFamily="Segoe MDL2 Assets" FontSize="18pt" Text="{Binding Icon}" />

  <TextBlock FontSize="18pt" Text="{Binding Content}" />

  </StackPanel>

  <TextBlock

  FontSize="11pt" Text="{Binding Note}" TextWrapping="Wrap" />

  </StackPanel>

  </Button>

  </Grid>

  </DataTemplate>

  </ItemsControl.ItemTemplate>

  <ItemsControl.ItemsPanel>

  <ItemsPanelTemplate>

  <WrapPanel HorizontalAlignment="Center" />

  </ItemsPanelTemplate>

  </ItemsControl.ItemsPanel>

  </ItemsControl>

 

  <Grid Grid.Column="1" Visibility="{Binding MenuModels[1].Visibility}">

  Text="{Binding MenuModels[1].Content}" />

 

  <Grid Grid.Column="1" Visibility="{Binding MenuModels[2].Visibility}">

  Text="{Binding MenuModels[2].Content}" />

 

  <Grid Grid.Column="1" Visibility="{Binding MenuModels[3].Visibility}">

  Text="{Binding MenuModels[3].Content}" />

 

  <Grid Background="#808080">

  <ItemsControl x:Name="MyItemsMenu" ItemsSource="{Binding MenuModels}">

  <ItemsControl.ItemTemplate>

  <DataTemplate>

  <Button

  Padding="10" Background="{Binding SideMenuBackground, Converter={StaticResource String2BrushConverter}}" BorderThickness="0"

  Command="{Binding DataContext.ClickMenu, ElementName=MyItemsMenu}" CommandParameter="{Binding}" Foreground="{Binding SideMenuForeground, Converter={StaticResource String2BrushConverter}}">

  <StackPanel>

  <TextBlock

  FontFamily="Segoe MDL2 Assets" FontSize="26pt" Text="{Binding Icon}"

  TextAlignment="Center" />

  <TextBlock

  FontSize="8pt" Text="{Binding Content}" TextAlignment="Center" />

  </StackPanel>

  </Button>

  </DataTemplate>

  </ItemsControl.ItemTemplate>

  <ItemsControl.ItemsPanel>

  <ItemsPanelTemplate>

  <StackPanel />

  </ItemsPanelTemplate>

  </ItemsControl.ItemsPanel>

  </ItemsControl>

  </Grid>

  </Window>

  ```

 

  using Prism.Commands;

  using Prism.Mvvm;

  using System;

  using System.Collections.ObjectModel;

  using System.Diagnostics;

  using System.Globalization;

  using System.Windows;

  using System.Windows.Data;

  using System.Windows.Media;

 

  namespace Questions329889

  {

  public class String2BrushConverter : IValueConverter

  public object Convert(object value, Type targetType, object parameter, CultureInfo culture)

  {

  if (value is string s)

  return new SolidColorBrush((Color)ColorConverter.ConvertFromString(s));

  return null;

  }

  public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) => throw new NotImplementedException();

 

  public class MenuModel : BindableBase

  public string SideMenuForeground { get => _SideMenuForeground; set => SetProperty(ref _SideMenuForeground, value); }

  private string _SideMenuForeground;

 

  public string SideMenuBackground { get => _SideMenuBackground; set => SetProperty(ref _SideMenuBackground, value); }

  private string _SideMenuBackground;

 

  public Visibility HomeMenuVisibility { get => _HomeMenuVisibility; set => SetProperty(ref _HomeMenuVisibility, value); }

  private Visibility _HomeMenuVisibility;

 

  public Visibility SideMenuVisibility { get => _SideMenuVisibility; set => SetProperty(ref _SideMenuVisibility, value); }

  private Visibility _SideMenuVisibility;

 

  public Visibility Visibility { get => _Visibility; set => SetProperty(ref _Visibility, value); }

  private Visibility _Visibility;

 

  public string Icon { get => _Icon; set => SetProperty(ref _Icon, value); }

  private string _Icon;

 

  public string Content { get => _Content; set => SetProperty(ref _Content, value); }

  private string _Content;

 

  public string Note { get => _Note; set => SetProperty(ref _Note, value); }

  private string _Note;

 

  public void ChangeParameter(bool visible)

  {

  if (visible) Debug.WriteLine($"Visible: {Content}");

  Visibility = visible ? Visibility.Visible : Visibility.Hidden;

  SideMenuBackground = visible ? "#fff" : null;

  SideMenuForeground = visible ? "#000" : "#fff";

  }

 

  public class MainViewModel : BindableBase

  public ObservableCollection<MenuModel> MenuModels { get; }

  public DelegateCommand<MenuModel> ClickMenu { get; }

 

  public MainViewModel()

  {

  MenuModels = new()

  {

  SideMenuBackground = "#fff",

  SideMenuForeground = "#000",

  HomeMenuVisibility = Visibility.Collapsed,

  Visibility = Visibility.Visible,

  Icon = "\xE10F",

  Content = "HOME",

  SideMenuForeground = "#fff",

  HomeMenuVisibility = Visibility.Visible,

  Visibility = Visibility.Hidden,

  Icon = "\xF157",

  Content = "CONTENT1",

  Note = "Content1 です。ここには、content1 の説明が入ります。",

  SideMenuForeground = "#fff",

  HomeMenuVisibility = Visibility.Visible,

  Visibility = Visibility.Hidden,

  Icon = "\xF158",

  Content = "CONTENT2",

  Note = "Content2 です。ここには、content2 の説明が入ります。",

  SideMenuForeground = "#fff",

  HomeMenuVisibility = Visibility.Visible,

  Visibility = Visibility.Hidden,

  Icon = "\xF159",

  Content = "CONTENT3",

  Note = "Content3 です。ここには、content3 の説明が入ります。",

  };

 

  ClickMenu = new(x =>

  {

  foreach (var m in MenuModels)

  m.ChangeParameter(x == m);

  });

  }

 

  public partial class MainWindow : Window

  public MainWindow() => InitializeComponent();

  }

  ```

 

  ---

 

  気になった点

  * ボタンの扱いがおかしい（文字等がある部分までマウスを入れないと反応しない）

  見た目を変えるにはテンプレートを当ててください。

  * `View`だけの関心が`ViewModel`（`MenuModel`）に染み出している

  `MenuModel`では選択されているという情報だけでいいと思います。

  * おそらく`TabControl`ですっきり書けそう

  見た目を同じにするとなると、スタイル等で行数は変わらないかも？