UdpClient.BeginSend Method

Reference

Definition

Namespace:: System.Net.Sockets

Assemblies:: netstandard.dll, System.Net.Sockets.dll

Assembly:: System.Net.Sockets.dll

Assembly:: System.dll

Assembly:: netstandard.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Sends a datagram to a remote host asynchronously.

Overloads

BeginSend(Byte[], Int32, String, Int32, AsyncCallback, Object)	Sends a datagram to a destination asynchronously. The destination is specified by the host name and port number.
BeginSend(Byte[], Int32, IPEndPoint, AsyncCallback, Object)	Sends a datagram to a destination asynchronously. The destination is specified by a EndPoint.
BeginSend(Byte[], Int32, AsyncCallback, Object)	Sends a datagram to a remote host asynchronously. The destination was specified previously by a call to Connect.

BeginSend(Byte[], Int32, String, Int32, AsyncCallback, Object)

Source:: UDPClient.cs

Source:: UDPClient.cs

Source:: UDPClient.cs

Sends a datagram to a destination asynchronously. The destination is specified by the host name and port number.

public:
 IAsyncResult ^ BeginSend(cli::array <System::Byte> ^ datagram, int bytes, System::String ^ hostname, int port, AsyncCallback ^ requestCallback, System::Object ^ state);

public IAsyncResult BeginSend(byte[] datagram, int bytes, string? hostname, int port, AsyncCallback? requestCallback, object? state);

public IAsyncResult BeginSend(byte[] datagram, int bytes, string hostname, int port, AsyncCallback requestCallback, object state);

member this.BeginSend : byte[] * int * string * int * AsyncCallback * obj -> IAsyncResult

Public Function BeginSend (datagram As Byte(), bytes As Integer, hostname As String, port As Integer, requestCallback As AsyncCallback, state As Object) As IAsyncResult

Parameters

datagram: Byte[]

A Byte array that contains the data to be sent.

bytes: Int32

The number of bytes to send.

hostname: String

The destination host.

port: Int32

The destination port number.

requestCallback: AsyncCallback

An AsyncCallback delegate that references the method to invoke when the operation is complete.

state: Object

A user-defined object that contains information about the send operation. This object is passed to the requestCallback delegate when the operation is complete.

Returns

IAsyncResult

An IAsyncResult object that references the asynchronous send.

Examples

The following code example uses BeginSend to asynchronously send a server request.

public:
    static bool isMessageSent;

    static void SendCallback(IAsyncResult^ asyncResult)
    {
        UdpClient^ udpClient = (UdpClient^)asyncResult->AsyncState;

        Console::WriteLine("number of bytes sent: {0}",
            udpClient->EndSend(asyncResult));
        isMessageSent = true;
    }

public static bool messageSent = false;

public static void SendCallback(IAsyncResult ar)
{
    UdpClient u = (UdpClient)ar.AsyncState;

    Console.WriteLine($"number of bytes sent: {u.EndSend(ar)}");
    messageSent = true;
}

public:
    static void SendMessage3(String^ server, String^ message)
    {
        // create the udp socket
        UdpClient^ udpClient = gcnew UdpClient();

        array<Byte>^ sendBytes = Encoding::ASCII->GetBytes(message);

        // send the message
        // the destination is defined by the server name and port
        udpClient->BeginSend(sendBytes, sendBytes->Length, server, listenPort,
            gcnew AsyncCallback(SendCallback), udpClient);

        // Do some work while we wait for the send to complete. For
        // this example, we'll just sleep
        while (!isMessageSent)
        {
            Thread::Sleep(100);
        }
    }

static void SendMessage3(string server, string message)
{
    // create the udp socket
    UdpClient u = new UdpClient();

    byte[] sendBytes = Encoding.ASCII.GetBytes(message);

    // send the message
    // the destination is defined by the server name and port
    u.BeginSend(sendBytes, sendBytes.Length, server, s_listenPort, new AsyncCallback(SendCallback), u);

    // Do some work while we wait for the send to complete. For this example, we'll just sleep
    while (!messageSent)
    {
        Thread.Sleep(100);
    }
}

Remarks

The asynchronous BeginSend operation must be completed by calling the EndSend method. Typically, the method is invoked by the requestCallback delegate.

This method does not block until the operation is complete. To block until the operation is complete, use one of the Send method overloads.

For detailed information about using the asynchronous programming model, see Calling Synchronous Methods Asynchronously.

Applies to

.NET 10 and other versions

Product	Versions
.NET	Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10
.NET Framework	2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard	2.0, 2.1

BeginSend(Byte[], Int32, IPEndPoint, AsyncCallback, Object)

Source:: UDPClient.cs

Source:: UDPClient.cs

Source:: UDPClient.cs

Sends a datagram to a destination asynchronously. The destination is specified by a EndPoint.

public:
 IAsyncResult ^ BeginSend(cli::array <System::Byte> ^ datagram, int bytes, System::Net::IPEndPoint ^ endPoint, AsyncCallback ^ requestCallback, System::Object ^ state);

public IAsyncResult BeginSend(byte[] datagram, int bytes, System.Net.IPEndPoint? endPoint, AsyncCallback? requestCallback, object? state);

public IAsyncResult BeginSend(byte[] datagram, int bytes, System.Net.IPEndPoint endPoint, AsyncCallback requestCallback, object state);

member this.BeginSend : byte[] * int * System.Net.IPEndPoint * AsyncCallback * obj -> IAsyncResult

Public Function BeginSend (datagram As Byte(), bytes As Integer, endPoint As IPEndPoint, requestCallback As AsyncCallback, state As Object) As IAsyncResult

Parameters

datagram: Byte[]

A Byte array that contains the data to be sent.

bytes: Int32

The number of bytes to send.

endPoint: IPEndPoint

The EndPoint that represents the destination for the data.

requestCallback: AsyncCallback

An AsyncCallback delegate that references the method to invoke when the operation is complete.

state: Object

A user-defined object that contains information about the send operation. This object is passed to the requestCallback delegate when the operation is complete.

Returns

IAsyncResult

An IAsyncResult object that references the asynchronous send.

Examples

The following code example uses BeginSend to asynchronously send a server request.

public:
    static bool isMessageSent;

    static void SendCallback(IAsyncResult^ asyncResult)
    {
        UdpClient^ udpClient = (UdpClient^)asyncResult->AsyncState;

        Console::WriteLine("number of bytes sent: {0}",
            udpClient->EndSend(asyncResult));
        isMessageSent = true;
    }

public static bool messageSent = false;

public static void SendCallback(IAsyncResult ar)
{
    UdpClient u = (UdpClient)ar.AsyncState;

    Console.WriteLine($"number of bytes sent: {u.EndSend(ar)}");
    messageSent = true;
}

public:
    static void SendMessage2(String^ server, String^ message)
    {
        // create the udp socket
        UdpClient^ udpClient = gcnew UdpClient();
        array<Byte>^ sendBytes = Encoding::ASCII->GetBytes(message);

        // resolve the server name
        IPHostEntry^ resolvedServer = Dns::GetHostEntry(server);

        IPEndPoint^ ipEndPoint =
            gcnew IPEndPoint(resolvedServer->AddressList[0], listenPort);

        // send the message
        // the destination is defined by the IPEndPoint
        udpClient->BeginSend(sendBytes, sendBytes->Length, ipEndPoint,
            gcnew AsyncCallback(SendCallback), udpClient);

        // Do some work while we wait for the send to complete. For
        // this example, we'll just sleep
        while (!isMessageSent)
        {
            Thread::Sleep(100);
        }
    }

static void SendMessage2(string server, string message)
{
    // create the udp socket
    UdpClient u = new UdpClient();
    byte[] sendBytes = Encoding.ASCII.GetBytes(message);

    // resolve the server name
    IPHostEntry heserver = Dns.GetHostEntry(server);

    IPEndPoint e = new IPEndPoint(heserver.AddressList[0], s_listenPort);

    // send the message
    // the destination is defined by the IPEndPoint
    u.BeginSend(sendBytes, sendBytes.Length, e, new AsyncCallback(SendCallback), u);

    // Do some work while we wait for the send to complete. For this example, we'll just sleep
    while (!messageSent)
    {
        Thread.Sleep(100);
    }
}

Remarks

The asynchronous BeginSend operation must be completed by calling the EndSend method. Typically, the method is invoked by the requestCallback delegate.

This method does not block until the operation is complete. To block until the operation is complete, use one of the Send method overloads.

For detailed information about using the asynchronous programming model, see Calling Synchronous Methods Asynchronously.

Applies to

.NET 10 and other versions

Product	Versions
.NET	Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10
.NET Framework	2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard	2.0, 2.1

BeginSend(Byte[], Int32, AsyncCallback, Object)

Source:: UDPClient.cs

Source:: UDPClient.cs

Source:: UDPClient.cs

Sends a datagram to a remote host asynchronously. The destination was specified previously by a call to Connect.

public:
 IAsyncResult ^ BeginSend(cli::array <System::Byte> ^ datagram, int bytes, AsyncCallback ^ requestCallback, System::Object ^ state);

public IAsyncResult BeginSend(byte[] datagram, int bytes, AsyncCallback? requestCallback, object? state);

public IAsyncResult BeginSend(byte[] datagram, int bytes, AsyncCallback requestCallback, object state);

member this.BeginSend : byte[] * int * AsyncCallback * obj -> IAsyncResult

Public Function BeginSend (datagram As Byte(), bytes As Integer, requestCallback As AsyncCallback, state As Object) As IAsyncResult

Parameters

datagram: Byte[]

A Byte array that contains the data to be sent.

bytes: Int32

The number of bytes to send.

requestCallback: AsyncCallback

An AsyncCallback delegate that references the method to invoke when the operation is complete.

state: Object

A user-defined object that contains information about the send operation. This object is passed to the requestCallback delegate when the operation is complete.

Returns

IAsyncResult

An IAsyncResult object that references the asynchronous send.

Examples

The following code example uses BeginSend to asynchronously send a server request.

public:
    static bool isMessageSent;

    static void SendCallback(IAsyncResult^ asyncResult)
    {
        UdpClient^ udpClient = (UdpClient^)asyncResult->AsyncState;

        Console::WriteLine("number of bytes sent: {0}",
            udpClient->EndSend(asyncResult));
        isMessageSent = true;
    }

public static bool messageSent = false;

public static void SendCallback(IAsyncResult ar)
{
    UdpClient u = (UdpClient)ar.AsyncState;

    Console.WriteLine($"number of bytes sent: {u.EndSend(ar)}");
    messageSent = true;
}

public:
    static void SendMessage1(String^ server, String^ message)
    {
        // create the udp socket
        UdpClient^ udpClient = gcnew UdpClient();

        udpClient->Connect(server, listenPort);
        array<Byte>^ sendBytes = Encoding::ASCII->GetBytes(message);

        // send the message
        // the destination is defined by the call to .Connect()
        udpClient->BeginSend(sendBytes, sendBytes->Length,
            gcnew AsyncCallback(SendCallback), udpClient);

        // Do some work while we wait for the send to complete. For
        // this example, we'll just sleep
        while (!isMessageSent)
        {
            Thread::Sleep(100);
        }
    }

static void SendMessage1(string server, string message)
{
    // create the udp socket
    UdpClient u = new UdpClient();

    u.Connect(server, s_listenPort);
    byte[] sendBytes = Encoding.ASCII.GetBytes(message);

    // send the message
    // the destination is defined by the call to .Connect()
    u.BeginSend(sendBytes, sendBytes.Length, new AsyncCallback(SendCallback), u);

    // Do some work while we wait for the send to complete. For this example, we'll just sleep
    while (!messageSent)
    {
        Thread.Sleep(100);
    }
}

Remarks

The asynchronous BeginSend operation must be completed by calling the EndSend method. Typically, the method is invoked by the requestCallback delegate.

This method does not block until the operation completes. To block until the operation is complete, use one of the Send method overloads.

For detailed information about using the asynchronous programming model, see Calling Synchronous Methods Asynchronously.

Applies to

.NET 10 and other versions

Product	Versions
.NET	Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10
.NET Framework	2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard	2.0, 2.1

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UdpClient.BeginSend Method

Definition

Overloads

BeginSend(Byte[], Int32, String, Int32, AsyncCallback, Object)

Parameters

Returns

Examples

Remarks

Applies to

BeginSend(Byte[], Int32, IPEndPoint, AsyncCallback, Object)

Parameters

Returns

Examples

Remarks

Applies to

BeginSend(Byte[], Int32, AsyncCallback, Object)

Parameters

Returns

Examples

Remarks

Applies to

Additional resources