Getting start for WPF

Create a project

• Create a WPF App (.NET Framework) project.
  • Have to use .NET Framework 4.7.2 or later, or .NET Core 3.0 or later.
• Install ReactiveProperty.WPF package from NuGet.

Edit codes

• Add Startup event handler on App class.
• Add code to initialize scheduler for ReactiveProperty classes.

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Threading.Tasks;
using System.Windows;
using Reactive.Bindings;
using Reactive.Bindings.Schedulers;

namespace WpfApp1
{
    public partial class App : Application
    {
        private void Application_Startup(object sender, StartupEventArgs e)
        {
            ReactivePropertyScheduler.SetDefault(new ReactivePropertyWpfScheduler(Dispatcher));
        }
    }
}

• Create a MainWindowViewModel.cs file.
• Edit files like following.

MainWindowViewModel.cs

using Reactive.Bindings;
using System;
using System.ComponentModel;
using System.Linq;
using System.Reactive.Linq;

namespace WpfApp1
{
    class MainWindowViewModel : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;

        public ReactiveProperty<string> Input { get; }
        public ReadOnlyReactiveProperty<string> Output { get; }

        public MainWindowViewModel()
        {
            Input = new ReactiveProperty<string>("");
            Output = Input
                .Delay(TimeSpan.FromSeconds(1))
                .Select(x => x.ToUpper())
                .ToReadOnlyReactiveProperty();
        }
    }
}

MainWindow.xaml

<Window x:Class="WpfApp1.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:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApp1"
        mc:Ignorable="d"
        Title="MainWindow"
        Height="350"
        Width="525">
    <Window.DataContext>
        <local:MainWindowViewModel />
    </Window.DataContext>
    <StackPanel>
        <Label Content="Input" />
        <TextBox Text="{Binding Input.Value, UpdateSourceTrigger=PropertyChanged}"
                 Margin="5" />
        <Label Content="Output" />
        <TextBlock Text="{Binding Output.Value}"
                   Margin="5" />
    </StackPanel>
</Window>

Launch the application.

After launching the app, you can see the below window. The output value was displayed to upper case, after 1sec from the input.