LocalCertificateSelectionCallback Delegate

Definition

Namespace:

System.Net.Security

Assembly:

System.Net.Security.dll

Selects the local Secure Sockets Layer (SSL) certificate used for authentication.

public delegate System::Security::Cryptography::X509Certificates::X509Certificate ^ LocalCertificateSelectionCallback(System::Object ^ sender, System::String ^ targetHost, X509CertificateCollection ^ localCertificates, X509Certificate ^ remoteCertificate, cli::array <System::String ^> ^ acceptableIssuers);

public delegate System.Security.Cryptography.X509Certificates.X509Certificate LocalCertificateSelectionCallback(object sender, string targetHost, X509CertificateCollection localCertificates, X509Certificate? remoteCertificate, string[] acceptableIssuers);

type LocalCertificateSelectionCallback = delegate of obj * string * X509CertificateCollection * X509Certificate * string[] -> X509Certificate

Public Delegate Function LocalCertificateSelectionCallback(sender As Object, targetHost As String, localCertificates As X509CertificateCollection, remoteCertificate As X509Certificate, acceptableIssuers As String()) As X509Certificate 

Parameters

sender

Object

An object that contains state information for this validation.

targetHost

String

The host server specified by the client.

localCertificates

X509CertificateCollection

An X509CertificateCollection containing local certificates.

remoteCertificate

X509Certificate

The certificate used to authenticate the remote party.

acceptableIssuers

String[]

A String array of certificate issuers acceptable to the remote party.

Return Value

X509Certificate

An X509Certificate used for establishing an SSL connection.

Examples

The following code example demonstrates a method implementation for this delegate.

static X509Certificate^ SelectLocalCertificate(
        Object^ sender, 
        String^ targetHost, 
        X509CertificateCollection^ localCertificates, 
        X509Certificate^ remoteCertificate, 
        array<String^>^ acceptableIssuers
)
{	
    Console::WriteLine("Client is selecting a local certificate.");
    if (acceptableIssuers != nullptr && 
            acceptableIssuers->Length > 0 &&
            localCertificates != nullptr &&
            localCertificates->Count > 0)
    {
        // Use the first certificate that is from an acceptable issuer.
        IEnumerator^ myEnum1 = localCertificates->GetEnumerator();
        while ( myEnum1->MoveNext() )
        {
            X509Certificate^ certificate = safe_cast<X509Certificate^>(myEnum1->Current);
            String^ issuer = certificate->Issuer;
            if ( Array::IndexOf( acceptableIssuers, issuer ) != -1 )
                return certificate;
        }
    }
    if (localCertificates != nullptr &&
            localCertificates->Count > 0)
        return localCertificates[0];
            
    return nullptr;
 }

public static X509Certificate SelectLocalCertificate(
    object sender,
    string targetHost,
    X509CertificateCollection localCertificates,
    X509Certificate remoteCertificate,
    string[] acceptableIssuers)
{	
    Console.WriteLine("Client is selecting a local certificate.");
    if (acceptableIssuers != null &&
        acceptableIssuers.Length > 0 &&
        localCertificates != null &&
        localCertificates.Count > 0)
    {
        // Use the first certificate that is from an acceptable issuer.
        foreach (X509Certificate certificate in localCertificates)
        {
            string issuer = certificate.Issuer;
            if (Array.IndexOf(acceptableIssuers, issuer) != -1)
                return certificate;
        }
    }
    if (localCertificates != null &&
        localCertificates.Count > 0)
        return localCertificates[0];

    return null;
}

The following code example demonstrates creating an instance of this delegate.

// Server name must match the host name and the name on the host's certificate. 
serverName = args[ 1 ];

// Create a TCP/IP client socket.
TcpClient^ client = gcnew TcpClient( serverName,5000 );
Console::WriteLine( L"Client connected." );

// Create an SSL stream that will close the client's stream.
SslStream^ sslStream = gcnew SslStream( 
    client->GetStream(),
    false,
    gcnew RemoteCertificateValidationCallback( ValidateServerCertificate ),
    gcnew LocalCertificateSelectionCallback( SelectLocalCertificate ) );

// Server name must match the host name and the name on the host's certificate.
serverName = args[0];
// Create a TCP/IP client socket.
TcpClient client = new TcpClient(serverName,5000);
Console.WriteLine("Client connected.");
// Create an SSL stream that will close the client's stream.
SslStream sslStream = new SslStream(
    client.GetStream(),
    false,
    new RemoteCertificateValidationCallback (ValidateServerCertificate),
    new LocalCertificateSelectionCallback(SelectLocalCertificate)
    );

Remarks

This delegate is used to construct instances of the SslStream class. The SslStream class is used to help secure information exchanged between a client and server. The client and server use this delegate to select a certificate to be used for authentication.

Extension Methods

GetMethodInfo(Delegate)

Gets an object that represents the method represented by the specified delegate.

See also

• RemoteCertificateValidationCallback