ProximityDevice.SubscribeForMessage(String, MessageReceivedHandler) 方法

定義

命名空間:

Windows.Networking.Proximity

建立指定之訊息類型的訂用帳戶。

public:
 virtual long long SubscribeForMessage(Platform::String ^ messageType, MessageReceivedHandler ^ messageReceivedHandler) = SubscribeForMessage;

long SubscribeForMessage(winrt::hstring const& messageType, MessageReceivedHandler const& messageReceivedHandler);

public long SubscribeForMessage(string messageType, MessageReceivedHandler messageReceivedHandler);

function subscribeForMessage(messageType, messageReceivedHandler)

Public Function SubscribeForMessage (messageType As String, messageReceivedHandler As MessageReceivedHandler) As Long

參數

messageType

String

Platform::String

winrt::hstring

要傳遞至此訂用帳戶的訊息類型。

messageReceivedHandler

MessageReceivedHandler

鄰近提供者會在傳遞訊息時呼叫的處理常式。

傳回

Int64

long long

long

訂用帳戶的唯一識別碼。

Windows 需求

應用程式功能

ID_CAP_PROXIMITY [Windows Phone] proximity ID_CAP_PROXIMITY [Windows Phone]

範例

Windows.Networking.Proximity.ProximityDevice proximityDevice;
long publishedMessageId = -1;
long subscribedMessageId = -1;

private void initializeProximityDevice()
{
    proximityDevice = Windows.Networking.Proximity.ProximityDevice.GetDefault();

    if (proximityDevice != null)
    {
        PublishMessageButton.Click += PublishMessage;
        SubscribeForMessageButton.Click += SubscribeForMessage;
        StopSubscribingForMessageButton.Click += StopSubscribingForMessage;
        StopPublishingMessageButton.Click += StopPublishingMessage;
    }
    else
    {
        WriteMessageText("Failed to initialized proximity device.\n");
    }
}

private void PublishMessage(object sender, RoutedEventArgs e)
{
    // Stop publishing the current message.
    if (publishedMessageId != -1)
    {
        proximityDevice.StopPublishingMessage(publishedMessageId);
    }

    publishedMessageId = 
        proximityDevice.PublishMessage("Windows.SampleMessage", MessageTextBlock.Text);
}

private void SubscribeForMessage(object sender, RoutedEventArgs e)
{
    // Only subscribe for the message one time.
    if (subscribedMessageId == -1)
    {
        subscribedMessageId = 
        proximityDevice.SubscribeForMessage("Windows.SampleMessage", messageReceived);
    }
}

private void messageReceived(
    Windows.Networking.Proximity.ProximityDevice device, 
    Windows.Networking.Proximity.ProximityMessage message)
{
    MessageBlock.Text += "Message received: " + message.DataAsString + "\n";
}

private void StopSubscribingForMessage(object sender, RoutedEventArgs e)
{
    proximityDevice.StopSubscribingForMessage(subscribedMessageId);
    subscribedMessageId = -1;
}

private void StopPublishingMessage(object sender, RoutedEventArgs e)
{
    proximityDevice.StopPublishingMessage(publishedMessageId);
    publishedMessageId = -1;
}

// Write a message to MessageBlock on the UI thread.
private Windows.UI.Core.CoreDispatcher messageDispatcher = Window.Current.CoreWindow.Dispatcher;

async private void WriteMessageText(string message, bool overwrite = false)
{
    await messageDispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal,
        () =>
        {
            if (overwrite)
                MessageBlock.Text = message;
            else
                MessageBlock.Text += message;
        });
}

Private proximityDevice As Windows.Networking.Proximity.ProximityDevice
Private publishedMessageId As Long = -1
Private subscribedMessageId As Long = -1

Private Sub initializeProximityDevice()
    proximityDevice = Windows.Networking.Proximity.ProximityDevice.GetDefault()

    If proximityDevice IsNot Nothing Then
        AddHandler PublishMessageButton.Click, AddressOf PublishMessage
        AddHandler SubscribeForMessageButton.Click, AddressOf SubscribeForMessage
        AddHandler StopSubscribingForMessageButton.Click, AddressOf StopSubscribingForMessage
        AddHandler StopPublishingMessageButton.Click, AddressOf StopPublishingMessage
    Else
        WriteMessageText("Failed to initialized proximity device." & vbTab)
    End If
End Sub

Private Sub PublishMessage(sender As Object, e As RoutedEventArgs)
    ' Stop publishing the current message.
    If publishedMessageId <> -1 Then
        proximityDevice.StopPublishingMessage(publishedMessageId)
    End If

    publishedMessageId =
        proximityDevice.PublishMessage("Windows.SampleMessage", MessageTextBlock.Text)
End Sub

Private Sub SubscribeForMessage(sender As Object, e As RoutedEventArgs)
    ' Only subscribe for the message one time.
    If subscribedMessageId = -1 Then
        subscribedMessageId =
        proximityDevice.SubscribeForMessage("Windows.SampleMessage", AddressOf messageReceived)
    End If
End Sub

Private Sub messageReceived(
    device As Windows.Networking.Proximity.ProximityDevice,
    message As Windows.Networking.Proximity.ProximityMessage)

    MessageBlock.Text &= "Message received: " & message.DataAsString & vbTab
End Sub

Private Sub StopSubscribingForMessage(sender As Object, e As RoutedEventArgs)
    proximityDevice.StopSubscribingForMessage(subscribedMessageId)
    subscribedMessageId = -1
End Sub

Private Sub StopPublishingMessage(sender As Object, e As RoutedEventArgs)
    proximityDevice.StopPublishingMessage(publishedMessageId)
    publishedMessageId = -1
End Sub

' Write a message to MessageBlock on the UI thread.
Private Async Sub WriteMessageText(message As String, Optional overwrite As Boolean = False)
    Await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal,
        Sub()
            If overwrite Then
                MessageBlock.Text = message
            Else
                MessageBlock.Text &= message
            End If
        End Sub)
End Sub

備註

在您的應用程式呼叫 SubscribeForMessage 方法之後，它會接收以相同訊息類型發佈 (的訊息，如任何代理裝置的 messageType 參數所指示) 。 如需不同訊息類型的詳細資訊，請參閱 PublishBinaryMessage (String、IBuffer) 參考主題中的備註。

您可以將 SubscribeForMessage 方法傳回的訂用帳戶識別碼傳遞至 StopSubscribingForMessage 方法，以取消訂閱。

您可以使用 PublishMessage、 PublishBinaryMessage或 PublishUriMessage 方法，將訊息發佈至訂閱者。

重要

鄰近 API 不提供驗證、加密或訊息完整性。 請勿使用鄰近性來交換使用者敏感性資訊，例如密碼、財務資料、簡訊、電子郵件、相片或政府識別碼。

另請參閱

• 鄰近性和點選 (C#/VB/C++)
• 鄰近性範例