c# - How to retrive value of listbox.valuemember property -

i beginner in c# programming. have filter result in mode:

listamicizie1.displaymember = "viewname"; // it's alias listamicizie1.valuemember = "idutente"; //it's primary key in db table listamicizie1.datasource = ds.tables["utenti"]; //db table 

now must register in db table value of result of listbox , use code

    string idu = string.empty;     string value = string.empty;     foreach (var item in listamicizie1.valuemember)     {                (int j = 0; j < listamicizie1.items.count; j++)        {            idu = listamicizie1.selectedvalue;            value += idu + ",";        }     }     value = value.trimend(',');     value = value.trimend(',');     idutente = user.text;     string cnnstr = system.configuration.configurationsettings.appsettings["cnnstr"].tostring();     string querysql2 = " insert amicizia (idutente1, [idamici]) values ('" + idutente + "', '" + value + "')";     sqlconnection myconn = new sqlconnection(cnnstr);     sqlcommand mycmd = new sqlcommand(querysql2, myconn);     try     {        myconn.open();        mycmd.executenonquery();     }     catch (exception ex)     {        messagebox.show(ex.tostring());     }         {        myconn.close();     }        }   this.close();  } 

the program running, when open second db table (amicizia), value in idamici isn't primary key ( idutente in first table),but i,d,u,t,e,n,t,e,.

how retrive original value of idutente? thanks

(sorry if write whit errors, i'm not english :) )

do not use value.trimend(','); use value.replace(',', '');

also practice use parameters instead of concatenated string.

        string idu = string.empty;         string value = string.empty;         foreach (var item in listamicizie1.valuemember)         {               (int j = 0; j < listamicizie1.items.count; j++)             {                 idu = listamicizie1.selectedvalue;                 value += idu + ",";             }         }         //value = value.trimend(',');         //value = value.trimend(',');         value = value.replace(',', '');         value = value.replace(' ', ''); //add line if not want space.          idutente = user.text;         string cnnstr = system.configuration.configurationsettings.appsettings["cnnstr"].tostring();         string querysql2 = " insert amicizia (idutente1, idamici) values ('" + @idutente,  @value)";         sqlconnection myconn = new sqlconnection(cnnstr);         sqlcommand mycmd = new sqlcommand(querysql2, myconn);         try         {             myconn.open();             mycmd.parameters.addwithvalue("@idutente", idutente);             mycmd.parameters.addwithvalue("@value", value);             mycmd.executenonquery();         }         catch (exception ex)         {             messagebox.show(ex.tostring());         }                 {             myconn.close();         }       }     this.close(); } 

added:

you can change code value += idu + ","; when generating value, see code

foreach (var item in listamicizie1.valuemember) {            (int j = 0; j < listamicizie1.items.count; j++)    {        idu = listamicizie1.selectedvalue;        value += idu.trim(idu);    } } //value = value.trimend(','); //value = value.trimend(','); 

now no need call replace

adding items list box **

try code.

        string cnnstr = system.configuration.configurationsettings.appsettings["cnnstr"].tostring();         string querysql2 = " insert amicizia (idutente1, idamici) values ('" + @idutente,  @value)";         sqlconnection myconn = new sqlconnection(cnnstr);         sqlcommand mycmd = new sqlcommand(querysql2, myconn);         myconn.open();          (int i=0; < listamicizie1.items.count; i++)         {             var myitem = listamicizie1.items[i];             var dataarray = ( myitem datarowview).row.itemarray;             //messagebox.show(dataarray[0].tostring());             idutente = user.text; //i don't know storing here.             value = dataarray[0].tostring(); //dataarray[0] should have key              try             {               mycmd.parameters.addwithvalue("@idutente", idutente);               mycmd.parameters.addwithvalue("@value", value);               mycmd.executenonquery();               mycmd.parameters.clear();             }             catch (exception ex)             {                messagebox.show(ex.tostring());                return;             }                         {               myconn.close();             }          }