DevicePacketStream.IsPacketAvailable Method

Artikel
09/25/2012

Checks if a packet is available to be read from the device packet stream.

Namespace: Microsoft.SmartDevice.Connectivity
Assembly: Microsoft.SmartDevice.Connectivity (in Microsoft.SmartDevice.Connectivity.dll)

Syntax

'Declaration
Public Function IsPacketAvailable As Boolean

'Usage
Dim instance As DevicePacketStream 
Dim returnValue As Boolean 

returnValue = instance.IsPacketAvailable()

public bool IsPacketAvailable()

public:
bool IsPacketAvailable()

public function IsPacketAvailable() : boolean

Return Value

Type: System.Boolean
true if there is data ready to be read; otherwise, false.

Exceptions

Exception	Condition
IOException	A COM or IO exception has occurred.

Remarks

A packet is available when a connected device agent writes a packet to the stream by calling Write.

Examples

' While stream is connected, try to read a packet. 
While ps.IsConnected()
    If ps.IsPacketAvailable() Then
        packet = ps.Read()
        While Not packet.IsEndOfPacket()
            Select Case packet.ReadDataType()
                Case DataType.BoolType
                    Dim boolValue As Boolean = packet.ReadBool()
                Case DataType.ByteArrayType
                    Dim buffer As Byte() = packet.ReadBytes()
                Case DataType.ByteType
                    Dim byteValue As Byte = packet.ReadByte()
                Case DataType.CharType
                    Dim charValue As Char = packet.ReadChar()
                Case DataType.Int32Type
                    Console.WriteLine("Int32Type:  " + packet.ReadInt32().ToString())
                Case DataType.StringType
                    Console.WriteLine("String:  " + packet.ReadString())
                Case Else 
            End Select 
        End While 
        Exit While 
    End If
    System.Threading.Thread.Sleep(1000)
End While
ps.Close()
device.Disconnect()

// While stream is connected, try to read a packet. 
while (ps.IsConnected())
{
    if (ps.IsPacketAvailable())
    {
        packet = ps.Read();
        while (!packet.IsEndOfPacket())
        {
            switch (packet.ReadDataType())
            {
                case DataType.BoolType:
                    bool boolValue = packet.ReadBool();
                    break;
                case DataType.ByteArrayType:
                    byte[] buffer = packet.ReadBytes();
                    break;
                case DataType.ByteType:
                    byte byteValue = packet.ReadByte();
                    break;
                case DataType.CharType:
                    char charValue = packet.ReadChar();
                    break;
                case DataType.Int32Type:
                    Console.WriteLine("Int32Type:  " + packet.ReadInt32().ToString());
                    break;
                case DataType.StringType:
                    Console.WriteLine("String:  " + packet.ReadString());
                    break;
                default:
                    break;
            }
        }
        break;
    }
    System.Threading.Thread.Sleep(1000);
}
ps.Close();
device.Disconnect();

.NET Framework Security

Full trust for the immediate caller. This member cannot be used by partially trusted code. For more information, see Using Libraries from Partially Trusted Code.

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