c# - trying to send email from database value -

i have method returning email address string chunk of code sends email, i'm getting error: "the specified string not in form required e-mail address."

here's method returns email address:

public static string getsignerbyid(int signerid) {     using (dbpsrentities10 myentities = new dbpsrentities10())     {         var thisid = myentities.refauthsigners.where(x => x.refauthsignerid == signerid).select(x => x.networkemail).tolist();          var formattedvalue = thisid.tostring();          return formattedvalue;      } } 

here's code sends email:

//method send approved email     public static void sendapprovedemail(string contactfirstname, string contactlastname, string contactemail, int signer)     {         //email 1         string filename = httpcontext.current.server.mappath("~/app_data/approvedemail.txt");         string mailbody = file.readalltext(filename);          mailbody = mailbody.replace("##contactfirstname##", contactfirstname);         mailbody = mailbody.replace("##contactlastname##", contactlastname);          mailmessage mymessage = new mailmessage();         mymessage.subject = "psr has been approved";         mymessage.body = mailbody;          string signeremailaddress = getsignerbyid(signer);          mymessage.from = new mailaddress("no-reply@test.com", "no-reply@test.com");         mymessage.to.add(new mailaddress(contactemail));         mymessage.to.add(new mailaddress(signeremailaddress));// email address database errors out.          smtpclient mysmtpclient = new smtpclient();         mysmtpclient.send(mymessage);     } 

any idea why variable "signeremailaddress" wouldn't work? value int database varchar(50) , valid email address. thanks!

thisid relturn list of network emails:

var thisid = myentities.refauthsigners                        .where(x => x.refauthsignerid == signerid)                        .select(x => x.networkemail)                        .tolist(); 

calling tostring() return list's type name. like:

"system.collections.generic.list`1[namespace.networkemail]" 

which not looks email address. possibly want use firstordefault() instead of tolist(). return network address of first signer provided id. should check whether returned value not null, , call tostring() (if have tostring() overridden on network email type).