UWPのListViewのItemTemplate内のボタンをクリックしたときにPageのDataContextにセットしたViewModelのメソッドを呼んでかつ押された行のデータが知りたい

blog.okazuki.jp

続きです。

senderのDataContextを引数に渡してくれるようなCallMethodActionを自作すればいいですね。

using Microsoft.Xaml.Interactivity;
using System.Reflection;
using Windows.UI.Xaml;

namespace App9
{
    public class TransferSenderDataContextCallMethodAction : DependencyObject, IAction
    {
        public object TargetObject
        {
            get { return (object)GetValue(TargetObjectProperty); }
            set { SetValue(TargetObjectProperty, value); }
        }

        // Using a DependencyProperty as the backing store for TargetObject.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty TargetObjectProperty =
            DependencyProperty.Register("TargetObject", typeof(object), typeof(TransferSenderDataContextCallMethodAction), new PropertyMetadata(null));

        public string MethodName
        {
            get { return (string)GetValue(MethodNameProperty); }
            set { SetValue(MethodNameProperty, value); }
        }

        // Using a DependencyProperty as the backing store for MethodName.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty MethodNameProperty =
            DependencyProperty.Register("MethodName", typeof(string), typeof(TransferSenderDataContextCallMethodAction), new PropertyMetadata(null));



        public object Execute(object sender, object parameter)
        {
            if (this.TargetObject == null || this.MethodName == null)
            {
                return null;
            }

            var methodInfo = this.TargetObject.GetType().GetTypeInfo().GetDeclaredMethod(this.MethodName);
            return methodInfo.Invoke(this.TargetObject, new object[] { (sender as FrameworkElement)?.DataContext });
        }
    }
}

こいつはこんな感じで使う。

<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:local="using:App9"
      xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
      xmlns:Interactivity="using:Microsoft.Xaml.Interactivity"
      xmlns:Core="using:Microsoft.Xaml.Interactions.Core"
      x:Class="App9.MainPage"
      mc:Ignorable="d"
      x:Name="Root">
    <Page.DataContext>
        <local:MainPageViewModel />
    </Page.DataContext>
    <Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
        <ListView ItemsSource="{x:Bind ViewModel.Items}">
            <ListView.ItemTemplate>
                <DataTemplate x:DataType="local:ItemViewModel">
                    <StackPanel>
                        <TextBlock Text="{x:Bind Value}" />
                        <Button Content="OKOK">
                            <Interactivity:Interaction.Behaviors>
                                <Core:EventTriggerBehavior EventName="Click">
                                    <local:TransferSenderDataContextCallMethodAction TargetObject="{Binding ElementName=Root, Path=DataContext}" MethodName="Alert" />
                                </Core:EventTriggerBehavior>
                            </Interactivity:Interaction.Behaviors>
                        </Button>
                    </StackPanel>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>
    </Grid>
</Page>

VMのメソッドは引数を増やしておきましょう。

using Prism.Mvvm;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;

// 空白ページのアイテム テンプレートについては、http://go.microsoft.com/fwlink/?LinkId=402352&clcid=0x409 を参照してください

namespace App9
{
    /// <summary>
    /// それ自体で使用できる空白ページまたはフレーム内に移動できる空白ページ。
    /// </summary>
    public sealed partial class MainPage : Page
    {
        public MainPageViewModel ViewModel => this.DataContext as MainPageViewModel;

        public MainPage()
        {
            this.InitializeComponent();
        }
    }

    public class MainPageViewModel : BindableBase
    {
        public ObservableCollection<ItemViewModel> Items { get; } = new ObservableCollection<ItemViewModel>
        {
            new ItemViewModel { Value = "Item1" },
            new ItemViewModel { Value = "Item2" },
            new ItemViewModel { Value = "Item3" },
        };

        public void Alert(ItemViewModel item)
        {
            Debug.WriteLine($"Alert {item.Value}");
        }
    }

    public class ItemViewModel : BindableBase
    {
        private string value;

        public string Value
        {
            get { return this.value; }
            set { this.SetProperty(ref this.value, value); }
        }

    }
}