如何：使用红外线传输文件

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：

• System

• System.Net

• System.Net.Sockets

• System.IO

• System.Windows.Forms

请参见

概念

红外连接

.NET Compact Framework 帮助主题