How to use ssh-rsa and SSH2 PUBLIC KEY in a C# application

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C#

SSH

I have an ssh-rsa and SSH2 PUBLIC KEY in text files(.txt), how can i use it to connect to a given server? A sample code will be very usefull.

What I have tried:

I have tried the following code, but i am getting the error Algoritham negotiation fail.

try
{
	string pkeypath = @"C://boa/xxx.key";
	Tamir.SharpSsh.Sftp objSFTP = new Tamir.SharpSsh.Sftp(ConfigurationManager.AppSettings["Server"].ToString(), ConfigurationManager.AppSettings["Username"].ToString(), ConfigurationManager.AppSettings["APassword"].ToString());
	objSFTP.AddIdentityFile(pkeypath);
	objSFTP.Connect();
}
catch (Exception ex)
{
	string x = ex.Message;
}