SslStream.Seek Method

Stream.Seek
Namespace: System.Net.Security
Assembly: System.dll

Syntax

public override long Seek(
	long offset,
	SeekOrigin origin
)

Parameters

offset: Type: System.Int64
The number of bytes to move in the stream.
origin: Type: System.IO.SeekOrigin
A System.IO.SeekOrigin enumeration that specifies the relative point of reference for the seek operation.

Return Value

Type: System.Int64
The new position within the stream.

Exceptions

Type	Condition
NotSupportedException	The stream does not support seeking.
ArgumentException	The value of origin is not valid. -or- The stream is in an invalid state.
ObjectDisposedException	The stream has been closed.

Type

Condition

NotSupportedException

The stream does not support seeking.

ArgumentException

The value of origin is not valid.

-or-

The stream is in an invalid state.

ObjectDisposedException

The stream has been closed.

Remarks

The Seek method allows you to change the current position of the stream. The offset parameter specifies how many bytes to move, and the origin parameter determines the starting point for the move.

For SslStream, seeking is generally not supported because the stream represents an encrypted and compressed communication channel. Operations like seeking are not meaningful in this context. If you attempt to call Seek on an SslStream, it will throw a NotSupportedException.

It is important to note that SslStream derives from Stream, which defines the Seek method. However, not all stream implementations support seeking.

Example

The following example demonstrates how an exception might be handled when attempting to seek on an SslStream.

            using System;
using System.Net.Security;
using System.Net.Sockets;
using System.IO;
using System.Security.Cryptography.X509Certificates;

public class SslStreamSeekExample
{
    public static void Main(string[] args)
    {
        // This example simulates attempting to use Seek and catching the exception.
        // A real SslStream would be obtained from a connected TcpClient.

        try
        {
            // In a real scenario, you would have an SslStream instance.
            // For demonstration, we create a dummy stream that will throw.
            // A typical SslStream is not seekable.
            using (var dummyStream = new MemoryStream()) // MemoryStream supports seek, but SslStream does not.
            {
                // Wrap a non-seekable stream in SslStream or simply use a direct SslStream
                // which will throw when Seek is called.
                // For illustration, let's assume we have an SslStream 'sslStream'
                // Example:
                // TcpClient client = new TcpClient("www.example.com", 443);
                // SslStream sslStream = new SslStream(client.GetStream());
                // sslStream.AuthenticateAsClient("www.example.com");

                // Since we can't easily create a live SslStream here for demonstration,
                // we'll rely on the known behavior that it throws NotSupportedException.

                Console.WriteLine("Attempting to seek on SslStream (expected to fail)...");

                // Imagine 'sslStream' is a valid SslStream object
                // For simulation purposes, let's throw the expected exception directly
                throw new NotSupportedException("Seeking is not supported on SslStream.");

                // If the above line were not there and 'sslStream' existed:
                // long newPosition = sslStream.Seek(0, SeekOrigin.Begin);
                // Console.WriteLine($"Seek successful. New position: {newPosition}");
            }
        }
        catch (NotSupportedException ex)
        {
            Console.ForegroundColor = ConsoleColor.Red;
            Console.WriteLine($"Caught expected exception: {ex.Message}");
            Console.ResetColor();
        }
        catch (Exception ex)
        {
            Console.ForegroundColor = ConsoleColor.Yellow;
            Console.WriteLine($"Caught unexpected exception: {ex.Message}");
            Console.ResetColor();
        }
    }
}
        

SeekOrigin Enumeration:

Begin: Specifies that the new position is relative to the start of the stream.
Current: Specifies that the new position is relative to the current stream position.
End: Specifies that the new position is relative to the end of the stream.

Requirements

Component	Version
.NET Framework	In .NET Framework 1.1 and later versions.
.NET Core / .NET 5+	Available in .NET Core and later versions.

.NET Framework

Methods