作ってみよう

WPFのプロジェクトを作ってUwpDesktopパッケージをNuGetからインストールします。SensorTagで使うUUIDを定義します。

namespace BleSample
{
    public class SensorTagUuid
    {
        // https://sensortag.codeplex.com/SourceControl/latest#SensorTagLibrary/SensorTagLibrary/Source/SensorTagUuid.cs
        public const string UuidIrtService = "f000aa00-0451-4000-b000-000000000000";
        public const string UuidIrtData = "f000aa01-0451-4000-b000-000000000000";
        public const string UuidIrtConf = "f000aa02-0451-4000-b000-000000000000";
    }
}

画面に初期化用ボタンと値を読み込み始めるボタンとデータ表示用TextBlockを置きます。

<Window x:Class="BleSample.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:BleSample"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525">
    <StackPanel>
        <Button Content="Connect"
                Click="ButtonConnect_Click" />
        <Button Content="Read value"
                Click="ButtonReadValue_Click" />
        <TextBlock x:Name="TextBlockTemp" />
    </StackPanel>
</Window>

そして、コードビハインドにUWPのAPIを使ってさくっとコードを書きましょう。

using System;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using System.Windows;
using Windows.Devices.Bluetooth.GenericAttributeProfile;
using Windows.Devices.Enumeration;
using Windows.Storage.Streams;

namespace BleSample
{
    /// <summary>
    /// MainWindow.xaml の相互作用ロジック
    /// </summary>
    public partial class MainWindow : Window
    {
        private GattDeviceService GattDeviceService { get; set; }

        private GattCharacteristic GattCharacteristic { get; set; }

        public MainWindow()
        {
            InitializeComponent();
        }

        private async void ButtonConnect_Click(object sender, RoutedEventArgs e)
        {
            // SensorTagを取得
            var selector = GattDeviceService.GetDeviceSelectorFromUuid(new Guid(SensorTagUuid.UuidIrtService));
            var devices = await DeviceInformation.FindAllAsync(selector);
            var deviceInformation = devices.FirstOrDefault();
            if (deviceInformation == null)
            {
                MessageBox.Show("not found");
                return;
            }

            this.GattDeviceService = await GattDeviceService.FromIdAsync(deviceInformation.Id);
            MessageBox.Show($"found {deviceInformation.Id}");

            // センサーの有効化?
            var configCharacteristic = this.GattDeviceService.GetCharacteristics(new Guid(SensorTagUuid.UuidIrtConf)).First();
            var status = await configCharacteristic.WriteValueAsync(new byte[] { 1 }.AsBuffer());
            if (status == GattCommunicationStatus.Unreachable)
            {
                MessageBox.Show("Initialize failed");
                return;
            }
        }

        private async void ButtonReadValue_Click(object sender, RoutedEventArgs e)
        {
            if (this.GattDeviceService == null)
            {
                MessageBox.Show("Please click connect button");
                return;
            }

            // 値を読み始める
            if (this.GattCharacteristic == null)
            {
                this.GattCharacteristic = this.GattDeviceService.GetCharacteristics(new Guid(SensorTagUuid.UuidIrtData)).First();
                this.GattCharacteristic.ValueChanged += this.GattCharacteristic_ValueChanged;

                var status = await this.GattCharacteristic.WriteClientCharacteristicConfigurationDescriptorAsync(GattClientCharacteristicConfigurationDescriptorValue.Notify);
                if (status == GattCommunicationStatus.Unreachable)
                {
                    MessageBox.Show("Failed");
                }
            }
        }

        private async void GattCharacteristic_ValueChanged(GattCharacteristic sender, GattValueChangedEventArgs args)
        {
            // 値を読んで表示する
            await this.Dispatcher.InvokeAsync(() =>
            {
                var data = new byte[args.CharacteristicValue.Length];
                DataReader.FromBuffer(args.CharacteristicValue).ReadBytes(data);
                var temp = BitConverter.ToUInt16(data, 2) / 128.0;
                this.TextBlockTemp.Text = $"{temp}℃";
            });
        }
    }
}