回答編集履歴

- `Settings.Designer.cs`を編集すれば可能です。

- が、`Settings.settings`のデザイナをいじったりすると消えやすいので、別に書いたほうが安全です（`partial`なので）

-

- `TaskList`が`MainWindowViewModel`経由になっている深い意味はありません。

-

- ```xaml

- <Window

- x:Class="Questions288214.Views.MainWindow"

- xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

- xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

- xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"

- xmlns:prism="http://prismlibrary.com/"

- xmlns:properties="clr-namespace:Questions288214.Properties"

- Width="{Binding Width, Mode=TwoWay, Source={x:Static properties:Settings.Default}}"

- Height="{Binding Height, Mode=TwoWay, Source={x:Static properties:Settings.Default}}"

- prism:ViewModelLocator.AutoWireViewModel="True"

- Left="{Binding Left, Mode=TwoWay, Source={x:Static properties:Settings.Default}}"

- Top="{Binding Top, Mode=TwoWay, Source={x:Static properties:Settings.Default}}">

- <Window.Resources>

- <BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter" />

- <Style TargetType="Label">

- <Setter Property="Margin" Value="5" />

- </Style>

- <Style TargetType="TextBox">

- <Setter Property="Margin" Value="5" />

- <Setter Property="VerticalAlignment" Value="Center" />

- <Setter Property="TextWrapping" Value="Wrap" />

- </Style>

- </Window.Resources>

- <i:Interaction.Triggers>

- <i:EventTrigger EventName="Closing">

- <prism:InvokeCommandAction Command="{Binding WindowClosingCommand}" />

- </i:EventTrigger>

- </i:Interaction.Triggers>

- <Grid>

- <Grid.ColumnDefinitions>

- <ColumnDefinition />

- <ColumnDefinition Width="2*" />

- </Grid.ColumnDefinitions>

- <Grid.RowDefinitions>

- <RowDefinition Height="Auto" />

- <RowDefinition />

- </Grid.RowDefinitions>

-

- <Grid>

- <Grid.ColumnDefinitions>

- <ColumnDefinition Width="Auto" />

- <ColumnDefinition />

- </Grid.ColumnDefinitions>

- <Label VerticalAlignment="Center" Content="表題" />

- <TextBox Grid.Column="1" Text="{Binding Txt_Title.Value, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

- </Grid>

-

- <Grid Grid.Column="1">

- <Grid.ColumnDefinitions>

- <ColumnDefinition Width="Auto" />

- <ColumnDefinition />

- <ColumnDefinition Width="Auto" />

- </Grid.ColumnDefinitions>

- <Label VerticalAlignment="Center" Content="Memo" />

- <TextBox Grid.Column="1" Text="{Binding Txt_Memo.Value, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

- <Button

- Grid.Column="2"

- MinWidth="56"

- Margin="5"

- Command="{Binding AddListCommand}"

- Content="追加" />

- </Grid>

-

- <ListBox

- x:Name="lst_Title"

- Grid.Row="1"

- Margin="5"

- DisplayMemberPath="Title"

- IsSynchronizedWithCurrentItem="True"

- ItemsSource="{Binding TaskList}"

- SelectionMode="Multiple">

- <ListBox.ItemContainerStyle>

- <Style TargetType="ListBoxItem">

- <Setter Property="IsSelected" Value="{Binding IsSelected.Value}" />

- </Style>

- </ListBox.ItemContainerStyle>

- </ListBox>

-

- <ListBox

- Grid.Row="1"

- Grid.Column="1"

- Margin="5"

- ItemsSource="{Binding TaskList}">

- <ListBox.ItemContainerStyle>

- <Style TargetType="ListBoxItem">

- <Setter Property="Visibility" Value="{Binding IsSelected.Value, Converter={StaticResource BooleanToVisibilityConverter}}" />

- </Style>

- </ListBox.ItemContainerStyle>

- <ListBox.ItemTemplate>

- <DataTemplate>

- <StackPanel>

- <TextBlock FontWeight="Bold" Text="{Binding Title}" />

- <TextBlock Text="{Binding Memo}" />

- </StackPanel>

- </DataTemplate>

- </ListBox.ItemTemplate>

- </ListBox>

- </Grid>

- </Window>

- ```

-

- ```C#

- using System.Collections.ObjectModel;

- using System.Reactive.Linq;

- using Prism.Mvvm;

- using Reactive.Bindings;

-

- namespace Questions288214.ViewModels

- {

- public class MainWindowViewModel : BindableBase

- {

- public ReactiveProperty<string> Txt_Title { get; set; } = new ReactiveProperty<string>();

- public ReactiveProperty<string> Txt_Memo { get; set; } = new ReactiveProperty<string>();

-

- public ObservableCollection<Task> TaskList

- {

- get => Properties.Settings.Default.TaskList;

- private set => Properties.Settings.Default.TaskList = value;

- }

-

- public ReactiveCommand AddListCommand { get; }

- public ReactiveCommand WindowClosingCommand { get; } = new ReactiveCommand();

-

-

- public MainWindowViewModel()

- {

- if(TaskList == null) TaskList = new ObservableCollection<Task>();

-

- AddListCommand = Txt_Title

- .Select(x => !string.IsNullOrEmpty(x))

- .ToReactiveCommand();

-

- AddListCommand.Subscribe(() =>

- {

- TaskList.Add(new Task { Title = Txt_Title.Value, Memo = Txt_Memo.Value, });

- Txt_Title.Value = "";

- Txt_Memo.Value = "";

- });

-

- WindowClosingCommand.Subscribe(() => Properties.Settings.Default.Save());

- }

- }

-

- public class Task

- {

- public string Title { get; set; }

- public string Memo { get; set; }

- public ReactiveProperty<bool> IsSelected { get; set; } = new ReactiveProperty<bool>();

- }

- }

-

- // 別ファイルに書けば安心

- namespace Questions288214.Properties

- {

- using Questions288214.ViewModels;

-

- internal sealed partial class Settings

- {

- [System.Configuration.UserScopedSetting()]

- [System.Diagnostics.DebuggerNonUserCode()]

- public ObservableCollection<Task> TaskList

- {

- get => (ObservableCollection<Task>)this[nameof(TaskList)];

- set => this[nameof(TaskList)] = value;

- }

- }

- }

- ```

-

- ウィンドウ位置保存用は普通にデザイナで入れたとする

- ```C#

- //------------------------------------------------------------------------------

- // <auto-generated>

- // このコードはツールによって生成されました。

- // ランタイム バージョン:4.0.30319.42000

- //

- // このファイルへの変更は、以下の状況下で不正な動作の原因になったり、

- // コードが再生成されるときに損失したりします。

- // </auto-generated>

- //------------------------------------------------------------------------------

-

- namespace Questions288214.Properties {

-

-

- [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]

- [global::System.CodeDom.Compiler.GeneratedCodeAttribute("Microsoft.VisualStudio.Editors.SettingsDesigner.SettingsSingleFileGenerator", "16.7.0.0")]

- internal sealed partial class Settings : global::System.Configuration.ApplicationSettingsBase {

-

- private static Settings defaultInstance = ((Settings)(global::System.Configuration.ApplicationSettingsBase.Synchronized(new Settings())));

-

- public static Settings Default {

- get {

- return defaultInstance;

- }

- }

-

- [global::System.Configuration.UserScopedSettingAttribute()]

- [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]

- [global::System.Configuration.DefaultSettingValueAttribute("NaN")]

- public double Top {

- get {

- return ((double)(this["Top"]));

- }

- set {

- this["Top"] = value;

- }

- }

-

- [global::System.Configuration.UserScopedSettingAttribute()]

- [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]

- [global::System.Configuration.DefaultSettingValueAttribute("NaN")]

- public double Left {

- get {

- return ((double)(this["Left"]));

- }

- set {

- this["Left"] = value;

- }

- }

-

- [global::System.Configuration.UserScopedSettingAttribute()]

- [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]

- [global::System.Configuration.DefaultSettingValueAttribute("525")]

- public double Width {

- get {

- return ((double)(this["Width"]));

- }

- set {

- this["Width"] = value;

- }

- }

-

- [global::System.Configuration.UserScopedSettingAttribute()]

- [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]

- [global::System.Configuration.DefaultSettingValueAttribute("350")]

- public double Height {

- get {

- return ((double)(this["Height"]));

- }

- set {

- this["Height"] = value;

- }

- }

- }

- }