在上篇里，我使用的是寄宿在WPF上的WCF进行两个程序间的通信，在解决问题的同时，我的同事也在思考能否使用UWP来做这件事。于是，我们发现了App Service，两个UWP应用沟通的桥梁。
App Service以background task 的形式允许一个UWP向其它UWP提供服务。
首先我们新建一个名为"MyCalculatorService"的Windows Runtime Component项目，新建Calculator类，实现 IBackgroundTask.接口，它很类似WCF里的ServiceContract。
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public sealed class Calculator : IBackgroundTask { private BackgroundTaskDeferral backgroundTaskDeferral; private AppServiceConnection appServiceConnection; public void Run(IBackgroundTaskInstance taskInstance) { this.backgroundTaskDeferral = taskInstance.GetDeferral(); var details = taskInstance.TriggerDetails as AppServiceTriggerDetails; appServiceConnection = details.AppServiceConnection; appServiceConnection.RequestReceived += OnRequestReceived; taskInstance.Canceled += OnTaskCanceled; } private async void OnRequestReceived(AppServiceConnection sender, AppServiceRequestReceivedEventArgs args) { var messageDeferral = args.GetDeferral(); ValueSet message = args.Request.Message; ValueSet returnData = new ValueSet(); string command = message["Command"] as string; //Add, Subtract, Multiply, Divide int? firstNumber = message["Input1"] as int?; int? secondNumber = message["Input2"] as int?; int? result = 0; if (firstNumber.HasValue && secondNumber.HasValue) { switch (command) { case "Add": { result = firstNumber + secondNumber; returnData.Add("Result", result.ToString()); returnData.Add("Status", "Complete"); break; } case "Subtract": { result = firstNumber - secondNumber; returnData.Add("Result", result.ToString()); returnData.Add("Status", "Complete"); break; } case "Multiply": { result = firstNumber * secondNumber; returnData.Add("Result", result.ToString()); returnData.Add("Status", "Complete"); break; } case "Divide": { result = firstNumber / secondNumber; returnData.Add("Result", result.ToString()); returnData.Add("Status", "Complete"); break; } default: { returnData.Add("Status", "Fail: unknown command"); break; } } } await args.Request.SendResponseAsync(returnData); messageDeferral.Complete(); } private void OnTaskCanceled(IBackgroundTaskInstance sender, BackgroundTaskCancellationReason reason) { if (this.backgroundTaskDeferral != null) { this.backgroundTaskDeferral.Complete(); } } } |
然后再新建一个名为MyCalculatorServiceProvider的UWP程序，充当服务端角色，相当于WCF宿主服务的。引用刚才我们创建的wind，然后在 Package.appxmanifest 中声明一个 名为CalculatorService1的App Service 实例，添加 入口点"MyCalculatorService.Calculator"。
现在我们来创建名为“CalculatorClient”的客户端，并调用以上服务。添加以下代码
public sealed partial class MainPage : Page
{
private AppServiceConnection calculatorService;
public MainPage()
{
this.InitializeComponent();
}
private async void button_Click(object sender, RoutedEventArgs e)
{
//Add the connection
if (calculatorService == null)
{
calculatorService = new AppServiceConnection();
calculatorService.AppServiceName = "CalculatorService1";
calculatorService.PackageFamilyName = "83da5395-2473-49fb-b361-37072e87e9b9_xe3s0d4n4696a";
var status = await calculatorService.OpenAsync();
if (status != AppServiceConnectionStatus.Success)
{
Result.Content = "Failed to connect";
return;
}
}
//Call the service
int num1 = int.Parse(InputtextBox1.Text);
int num2 = int.Parse(InputtextBox2.Text);
var message = new ValueSet();
message.Add("Command", Operation.SelectionBoxItem);
message.Add("Input1", num1);
message.Add("Input2", num2);
AppServiceResponse response = await calculatorService.SendMessageAsync(message);
string result = "";
if (response.Status == AppServiceResponseStatus.Success)
{
//Get the data that the service sent
if (response.Message["Status"] as string == "Complete")
{
result = response.Message["Result"] as string;
}
}
message.Clear();
ResulttextBlock.Text = result;
}
}
注意其中的AppServiceName是我们在MyCalculatorServiceProvider项目中定义的App Service的Name，PackageFamilyName 是MyCalculatorServiceProvider项目的PackageFamilyName。
完成后，先部署MyCalculatorServiceProvider再部署CalculatorClient，效果是不是跟WCF很类似呢？
示例demo可以从这里下http://www.cnblogs.com/luquanmingren/p/7692305.html，没错，我就是懒