如何：使用红外线传输文件

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更新：2007 年 11 月

.NET Compact Framework 为设备之间的红外线通信提供类。此示例演示了如何使用红外线通信在设备之间发送和接收文件。您需要两台 Pocket PC，分别用于发送和接收文件。

此示例创建一个 IrDAClient 实例，并使用其 DiscoverDevices 方法来搜索范围内的红外线设备。此方法返回一个 IrDADeviceInfo 对象数组，用于提供每台设备的信息。

此示例提供了文件发送和接收代码，这些代码可以通过“发送”和“接收”按钮进行演示。您至少应为一台设备创建“发送”应用程序，为另一台设备创建“接收”应用程序。

“发送”按钮只会将文件发送到侦听文件发送请求的设备。因此，在发送设备上点击“发送”按钮之前，必须先在接收设备上点击“接收”按钮。执行以下任务：

  • 获取要发送的文件流。

  • 使用为此应用程序确定的服务名创建一个 IrDAClient 实例。通过指定服务名来建立红外线连接，只要参与设备引用相同的名称，则服务名可以为任何值。在此示例中，服务名为“IrDATest”。

  • 将文件流读入发送该文件的 IrDAClient 流。

“接收”按钮将创建一个 IrDAListener 实例，以侦听服务名与发送设备中的 IrDAClient 实例相同的设备。

执行以下任务：

  • 创建将传输内容写入“我的文档”文件夹中的接收文件的流。

  • 使用发送设备的设备 ID 和服务名创建 IrDAEndPoint 实例。

  • 基于 IrDAEndPoint 实例创建一个 IrDAListener 实例并启动侦听服务。

  • 使用 AcceptIrDAClient 方法基于 IrDAListener 实例创建一个 IrDAClient 实例。

  • 读取 IrDAClient 实例的基础流，其中包含传输文件的数据。

  • 将该数据流写入 Receive.txt 文件的流。

创建应用程序

  1. 为发送设备创建 Pocket PC 应用程序，并向窗体添加按钮。将该按钮命名为“发送”。

  2. 在“我的文档”文件夹中创建名为 Send.txt 的文件。

  3. 在“发送”按钮的 Click 事件中添加以下代码。

    ' Align the infrared ports of the devices.
' Click the Receive button first, then click Send.
Private Sub SendButton_Click(sender As Object, e As System.EventArgs) _
    Handles SendButton.Click

    Dim irClient As New IrDAClient()
    Dim irServiceName As String = "IrDATest"
    Dim irDevices() As IrDADeviceInfo
    Dim buffersize As Integer = 256

    ' Create a collection of devices to discover.
    irDevices = irClient.DiscoverDevices(2)

    ' Show the name of the first device found.
    If irDevices.Length = 0 Then
        MessageBox.Show("No remote infrared devices found.")
        Return
    End If

    Try
        Dim irEndP As New IrDAEndPoint(irDevices(0).DeviceID, _
            irServiceName)
        Dim irListen As New IrDAListener(irEndP)
        irListen.Start()
        irClient = irListen.AcceptIrDAClient()
        MessageBox.Show("Connected!")

    Catch exSoc As SocketException
         MessageBox.Show("Couldn't listen on service " & irServiceName & ": " _
            & exSoc.ErrorCode)
    End Try

    ' Open a file to send and get its stream.
    Dim fs As Stream
    Try
        fs = New FileStream(".\My Documents\send.txt", FileMode.Open)
    Catch exFile As Exception
        MessageBox.Show("Cannot open " & exFile.ToString())
        Return
    End Try

    ' Get the underlying stream of the client.
    Dim baseStream As Stream = irClient.GetStream()

    ' Get the size of the file to send
    ' and write its size to the stream.
    Dim length As Byte() = BitConverter.GetBytes(fs.Length)
    baseStream.Write(length, 0, length.Length)

    ' Create a buffer for reading the file.
    Dim buffer(buffersize) As Byte

    Dim fileLength As Integer = CInt(fs.Length)

    Try
        ' Read the file stream into the base stream.
        While fileLength > 0
            Dim numRead As Int64 = fs.Read(buffer, 0, buffer.Length)
            baseStream.Write(buffer, 0, numRead)
            fileLength -= numRead
        End While
        MessageBox.Show("File sent")
    Catch exSend As Exception
        MessageBox.Show(exSend.Message)
    End Try

    fs.Close()
    baseStream.Close()
    irClient.Close()
End Sub

    // Align the infrared ports of the devices.
// Click the Receive button first, then click Send.
private void SendButton_Click(object sender, System.EventArgs e)
{
    IrDAClient irClient = new IrDAClient();
    string irServiceName = "IrDATest";
    IrDADeviceInfo[] irDevices;
    int buffersize = 256;

    // Create a collection of devices to discover.
    irDevices = irClient.DiscoverDevices(2);

    // Show the name of the first device found.
    if ((irDevices.Length == 0)) 
    {
        MessageBox.Show("No remote infrared devices found.");
        return;
    }
    try 
    {
        IrDAEndPoint irEndP = 
            new IrDAEndPoint(irDevices[0].DeviceID, irServiceName);
        IrDAListener irListen = new IrDAListener(irEndP);
        irListen.Start();
        irClient = irListen.AcceptIrDAClient();
        MessageBox.Show("Connected!");
    }
    catch (SocketException exSoc) 
    {
        MessageBox.Show(("Couldn\'t listen on service "
                        + (irServiceName + (": " + exSoc.ErrorCode))));
    }

    // Open a file to send and get its stream.
    Stream fs;
    try 
    {
        fs = new FileStream(".\\My Documents\\send.txt", FileMode.Open);
    }
    catch (Exception exFile) 
    {
        MessageBox.Show(("Cannot open " + exFile.ToString()));
        return;
    }

    // Get the underlying stream of the client.
    Stream baseStream = irClient.GetStream();

    // Get the size of the file to send
    // and write its size to the stream.
    byte[] length = BitConverter.GetBytes(fs.Length);
    baseStream.Write(length, 0, length.Length);

    // Create a buffer for reading the file.
    byte[] buffer = new byte[buffersize];
    int fileLength = (int) fs.Length;
    try 
    {
        // Read the file stream into the base stream.
        while ((fileLength > 0)) 
        {
            Int64 numRead = fs.Read(buffer, 0, buffer.Length);
            baseStream.Write(buffer, 0, Convert.ToInt32(numRead));
            fileLength = (fileLength - Convert.ToInt32(numRead));
        }
        MessageBox.Show("File sent");
    }
    catch (Exception exSend) 
    {
        MessageBox.Show(exSend.Message);
    }
    fs.Close();
    baseStream.Close();
    irClient.Close();
}

  4. 为接收设备创建 Pocket PC 应用程序，并向窗体添加按钮。将该按钮命名为“接收”。

  5. 在“接收”按钮的 Click 事件中添加以下代码。

    ' Align the infrared ports of the devices.
' Click the Receive button first, then click Send.
Private Sub ReceiveButton_Click(sender As Object, e As System.EventArgs) _
    Handles ReceiveButton.Click

    Dim irDevices() As IrDADeviceInfo
    Dim irClient As New IrDAClient()
    Dim irServiceName As String = "IrDATest"

    Dim buffersize As Integer = 256

    ' Create a collection for discovering up to
    ' three devices, although only one is needed.
    irDevices = irClient.DiscoverDevices(2)

    ' Cancel if no devices are found.
    If irDevices.Length = 0 Then
        MessageBox.Show("No remote infrared devices found.")
        Return
    End If

    ' Connect to the first IrDA device
    Dim irEndP As New IrDAEndPoint(irDevices(0).DeviceID, irServiceName)
    irClient.Connect(irEndP)

    ' Create a stream for writing a Pocket Word file.
    Dim writeStream As Stream
    Try
        writeStream = New FileStream(".\My Documents\receive.txt", _
            FileMode.OpenOrCreate)
    Catch
        MessageBox.Show("Cannot open file for writing.")
        Return
    End Try

    ' Get the underlying stream of the client.
    Dim baseStream As Stream = irClient.GetStream()

    ' Create a buffer for reading the file.
    Dim buffer(buffersize) As Byte

    Dim numToRead, numRead As Int64

    ' Read the file into a stream 8 bytes at a time.
    ' Because the stream does not support seek operations,
    ' its length cannot be determined.
    numToRead = 8

    Try    
        While numToRead > 0
            numRead = baseStream.Read(buffer, 0, numToRead)
            numToRead -= numRead
        End While
    Catch exReadIn As Exception
        MessageBox.Show("Read in: " & exReadIn.Message)
    End Try

    ' Get the size of the buffer to show
    ' the number of bytes to write to the file.
    numToRead = BitConverter.ToInt64(buffer, 0)

    Try
        ' Write the stream to the file until
        ' there are no more bytes to read.
        While numToRead > 0
            numRead = baseStream.Read(buffer, 0, buffer.Length)
            numToRead -= numRead
            writeStream.Write(buffer, 0, numRead)
        End While
        writeStream.Close()
        MessageBox.Show("File received.")
    Catch exWriteOut As Exception
        MessageBox.Show("Write out: " & exWriteOut.Message)
    End Try

     baseStream.Close()
     irClient.Close()
End Sub

    // Align the infrared ports of the devices.
// Click the Receive button first, then click Send.
private void ReceiveButton_Click(object sender, System.EventArgs e)
{
    IrDADeviceInfo[] irDevices;
    IrDAClient irClient = new IrDAClient();
    string irServiceName = "IrDATest";
    int buffersize = 256;

    // Create a collection for discovering up to
    // three devices, although only one is needed.
    irDevices = irClient.DiscoverDevices(2);

    // Cancel if no devices are found.
    if ((irDevices.Length == 0)) 
    {
        MessageBox.Show("No remote infrared devices found.");
        return;
    }

    // Connect to the first IrDA device
    IrDAEndPoint irEndP = 
        new IrDAEndPoint(irDevices[0].DeviceID, irServiceName);
    irClient.Connect(irEndP);

    // Create a stream for writing a Pocket Word file.
    Stream writeStream;
    try 
    {
        writeStream = new FileStream(".\\My Documents\\receive.txt", 
            FileMode.OpenOrCreate);
    }
    catch (Exception Ex)
    {
        MessageBox.Show("Cannot open file for writing. " + Ex.Message);
        return;
    }

    // Get the underlying stream of the client.
    Stream baseStream = irClient.GetStream();

    // Create a buffer for reading the file.
    byte[] buffer = new byte[buffersize];
    Int64 numToRead;
    Int64 numRead;

    // Read the file into a stream 8 bytes at a time.
    // Because the stream does not support seek operations, its
    // length cannot be determined.
    numToRead = 8;
    try 
    {
        while ((numToRead > 0)) 
        {
            numRead = baseStream.Read(buffer, 0, 
                Convert.ToInt32(numToRead));
            numToRead = (numToRead - numRead);
        }
    }
    catch (Exception exReadIn) {
        MessageBox.Show(("Read in: " + exReadIn.Message));
    }

    // Get the size of the buffer to show
    // the number of bytes to write to the file.
    numToRead = BitConverter.ToInt64(buffer, 0);
    try 
    {
        // Write the stream to the file until
        // there are no more bytes to read.
        while ((numToRead > 0)) {
            numRead = baseStream.Read(buffer, 0, buffer.Length);
            numToRead = (numToRead - numRead);
            writeStream.Write(buffer, 0, Convert.ToInt32(numRead));
        }
        writeStream.Close();
        MessageBox.Show("File received.");
    }
    catch (Exception exWriteOut) 
    {
        MessageBox.Show(("Write out: " + exWriteOut.Message));
    }
    baseStream.Close();
    irClient.Close();
}

运行应用程序

  1. 将应用程序部署到设备并启动这些应用程序。

  2. 对齐设备的红外端口。

  3. 点击接收设备上的“接收”按钮。

  4. 点击发送设备上的“发送”按钮。

  5. 检查是否已在“我的文档”文件夹中创建 Receive.txt 文件。

编译代码

此示例需要引用下面的命名空间：

请参见

概念

红外连接

.NET Compact Framework 帮助主题