Asp.net code-behind login errors? - asp.net

Question

I am getting an error when it is determining whether the username is false or not. I am using asp.net in code-behind. It is highlighted below. If someone can tell me what the error is that would be amazing!
protected void Login_Authenticate(object sender, AuthenticateEventArgs e)
{
Boolean blnresult;
blnresult = false;
**blnresult = Authentication(Login.UserName);**
if (blnresult == true)
{
e.Authenticated = true;
Session["Check"] = true;
}
else
e.Authenticated = false;
}
private bool Authentication(TextBox textBox)
{
throw new NotImplementedException();
}
protected static Boolean Authentication(string Username, string Password)
{
string sqlstring;
sqlstring = "SELECT userID FROM import_log.dbo.user_verification WHERE userID =" + Username + "";
System.Data.SqlClient.SqlConnection con = new System.Data.SqlClient.SqlConnection("Data Source = ietm-fwb-sql1; Initial Catalog = import_log; Persist Security Info = True; User ID = sa; Password = fwbadmin");
System.Data.SqlClient.SqlCommand comm = new System.Data.SqlClient.SqlCommand(sqlstring, con);
System.Data.SqlClient.SqlDataReader reader;
con.Open();
reader = comm.ExecuteReader();
if (reader.Read())
return true;
else
return false;
}
}
}