Why is SshHostKeyFingerprint needed when SshPrivateKeyPath is set to private key file

When I connect manually using the GUI WinSCP client to an SFTP site, I specify Host Name, User Name and Private Key File. No password or fingerprint is needed to connect. However, when I try to connect through the .NET client by specifying the same corresponding properties, I get this error:

System.ArgumentException: SessionOptions.Protocol is Protocol.Sftp or Protocol.Scp, but SessionOptions.SshHostKeyFingerprint is not set.

Is there a default value set for this property when using the Windows GUI client that I need to set directly when using the .NET client?

Orionsg wrote:

When I connect manually using the GUI WinSCP client to an SFTP site, I specify Host Name, User Name and Private Key File. No password or fingerprint is needed to connect.

That's not true. On the first connect, you are prompted to verify a public key of the server.

You are absolutely correct :).
I did not have to enter anything, but there was a message with the public key.

In the meanwhile I have studied the Session class a bit further and found the ScanFingerprint method to get the public key, including the example. Using this, I was able to get my code to work as expected.

Thanks for your reply and the awesome client!

Note that you should use the ScanFingerprint only to implement an interactive prompt to get the public key verified by an user.
You should not use it to automatically accept the key! That does not make you safe. It would be effectively the same as setting the SessionOptions.GiveUpSecurityAndAcceptAnySshHostKey.

See SessionOptions.Protocol is Protocol.Sftp or Protocol.Scp, but SessionOptions.SshHostKeyFingerprint is not set

I am having the same issue,

@SK: So please follow the link included in my previous post.