NegotiateStream::BeginAuthenticateAsClient Method (NetworkCredential^, ChannelBinding^, String^, ProtectionLevel, TokenImpersonationLevel, AsyncCallback^, Object^)
Called by clients to begin an asynchronous operation to authenticate the client, and optionally the server, in a client-server connection. The authentication process uses the specified credentials, authentication options, and channel binding. This method does not block.
Assembly: System (in System.dll)
public: [HostProtectionAttribute(SecurityAction::LinkDemand, ExternalThreading = true)] virtual IAsyncResult^ BeginAuthenticateAsClient( NetworkCredential^ credential, ChannelBinding^ binding, String^ targetName, ProtectionLevel requiredProtectionLevel, TokenImpersonationLevel allowedImpersonationLevel, AsyncCallback^ asyncCallback, Object^ asyncState )
Parameters
- credential
-
Type:
System.Net::NetworkCredential^
The NetworkCredential that is used to establish the identity of the client.
- binding
-
Type:
System.Security.Authentication.ExtendedProtection::ChannelBinding^
The ChannelBinding that is used for extended protection.
- targetName
-
Type:
System::String^
The Service Principal Name (SPN) that uniquely identifies the server to authenticate.
- requiredProtectionLevel
-
Type:
System.Net.Security::ProtectionLevel
One of the ProtectionLevel values, indicating the security services for the stream.
- allowedImpersonationLevel
-
Type:
System.Security.Principal::TokenImpersonationLevel
One of the TokenImpersonationLevel values, indicating how the server can use the client's credentials to access resources.
- asyncCallback
-
Type:
System::AsyncCallback^
An AsyncCallback delegate that references the method to invoke when the authentication is complete.
- asyncState
-
Type:
System::Object^
A user-defined object containing information about the write operation. This object is passed to the asyncCallback delegate when the operation completes.
Return Value
Type: System::IAsyncResult^An IAsyncResult object indicating the status of the asynchronous operation.
| Exception | Condition |
|---|---|
| ArgumentNullException | credential is null. - or - targetName is null. |
| AuthenticationException | The authentication failed. You can use this object to retry the authentication. |
| InvalidCredentialException | The authentication failed. You can use this object to retry the authentication. |
| InvalidOperationException | Authentication has already occurred. - or - This stream was used previously to attempt authentication as the server. You cannot use the stream to retry authentication as the client. |
| ObjectDisposedException | This object has been closed. |
Use the requiredProtectionLevel parameter to request security services for data transmitted using the authenticated stream. For example, to have the data encrypted and signed, specify the EncryptAndSign value. Successful authentication does not guarantee that the requested ProtectionLevel has been granted. You must check the IsEncrypted and IsSigned properties to determine what security services are used by the NegotiateStream.
This method is asynchronous and does not block while the operation completes. To block until the operation completes, use one of the AuthenticateAsClient method overloads.
The asynchronous authentication operation must be completed by calling the EndAuthenticateAsClient method. Typically, the method is invoked by the asyncCallback delegate. For detailed information about using the asynchronous programming model, see Calling Synchronous Methods Asynchronously
If the authentication fails, you receive an AuthenticationException or an InvalidCredentialException. In this case, you can retry the authentication with a different credential.
Available since 2.0