c# - Invalid input - format string ASP.NET -

hello i'm quite new in asp.net programming

dropdownlist code:

protected void dropdownlist1_selectedindexchanged(object sender, eventargs e) {     sqlconnection test = new sqlconnection("data source=michaŁ-komputer;initial catalog=projektnet_s10772;integrated security=true");      sqlcommand com;     string str;     test.open();     str = "select * klient klient_id='" + dropdownlist1.text.trim() + "'";     com = new sqlcommand(str, test);     sqldatareader reader = com.executereader();     if (reader.read())     {         txtimie2.text = reader["imie"].tostring();         txtnazwisko2.text = reader["nazwisko"].tostring();         txtemail2.text = reader["adres_email"].tostring();         txttelefon2.text = reader["telefon"].tostring();         txtmiasto2.text = reader["miasto"].tostring();         reader.close();         test.close();     } } 

update code

 protected void btnedytuj1_click(object sender, eventargs e) {     sqlconnection edytuj = new sqlconnection("data source=michaŁ-komputer;initial catalog=projektnet_s10772;integrated security=true");     {          sqlcommand cmd = new sqlcommand("update klient set imie='"+txtimie2.text+"', nazwisko='"+txtnazwisko+"', adres_email='"+txtemail2+"', telefon='"+txttelefon2+"', miasto='"+txtmiasto2+"' klient_id='"+convert.toint32 (txtmiasto2.text).tostring()+"'", edytuj);          edytuj.open();         cmd.executenonquery();         edytuj.close();         gridview3.databind();     } } 

what i'm trying do: i'm trying update grindview form ( using txtboxes located outside of grindview form ) dropdownlist list working expected (fullfiling textboxes date grindview ) - update buttton isn't. when i'm running updated code form i'm getting

invalid input - format string

row 141: sqlcommand cmd = new sqlcommand("update klient set imie='" +txtimie2.text+"', nazwisko='"+txtnazwisko+"', adres_email='"+txtemail2+"', telefon='" +txttelefon2+"', miasto='"+txtmiasto2 +"' klient_id='"+convert.toint32 (txtmiasto2.text).tostring()+"'", edytuj); 

could try me? thank

you should work on code:

using (sqlconnection edytuj = new sqlconnection("data source=michaŁ-komputer;initial catalog=projektnet_s10772;integrated security=true")) using (sqlcommand cmd = new sqlcommand("update klient set imie=@imie, nazwisko=@nazwisko, adres_email=@email, telefon=@telefon, miasto=@miasto klient_id=@id", edytuj)) {      cmd.parameters.addwithvalue("@imie", txtimie2.text);     cmd.parameters.addwithvalue("@nazwisko", txtnazwisko.text);     cmd.parameters.addwithvalue("@email", txtemail2.text);     cmd.parameters.addwithvalue("@telefon", txttelefon2.text);     cmd.parameters.addwithvalue("@miasto", txtmiasto2.text);     cmd.parameters.addwithvalue("@id", ""); //set proper id     cmd.executenonquery();     gridview3.databind(); }