c# - How to check the System.Net.Mail.SmtpClient.Credential -

i want check if have input right senderemail , mailpassword.what should do?the code :

        //邮箱地址//emailaddress         string server = combobox.text;         string sendermail = emailname.text.tostring().trim()+server;         messagebox.show("邮箱地址为：" + sendermail);         //邮箱密码//emailpassword         string mailpassword = emailpassword.text.tostring().trim();         //发送服务器//senderserver         server = server.substring(1);         string sendserver = "smtp."+server;         messagebox.show(sendserver);         //新建smtp客户端实例//create smtpclient          system.net.mail.smtpclient client = new system.net.mail.smtpclient(sendserver, 25);         client.credentials = new system.net.networkcredential(sendermail, mailpassword);         if (?????) { messagebox.show("success!"); } 

to check if senderemail correct can use mailaddress class

        try         {             new mailaddress(senderemail);                         }         catch (formatexception ex)         {             //the email address not correct         }