asp.net - How to get ID against selected value of Dropdownlist C# -

i have 2 question

1. how id against selected value of dropdownlist binded db?

2. then how insert id in other table ?

kindly explain code..

thanx in advance

to id code

string query = "select id table-1 name=" + dropdwonlist.selectedvalue; sqlcommand cmd = new sqlcommand(query, con); sqldatareader dr = cmd.executereader(); string getid = dr[0].tostring(); 

dropdownlist binding code

string query = "select id, name table-1"; sqlconnection con = new sqlconnection(constr); sqldataadapter da = new sqldataadapter(query, con); datatable dt = new datatable(); da.fill(dt); dropdwonlist.datasource = dt; dropdwonlist.datatextfield = "name"; dropdwonlist.datavaluefield = "id"; dropdwonlist.databind(); dropdwonlist.items.insert(0, new listitem("--select name--")); 

1) string id = dropdwonlist.selectedvalue;

2)

to insert table use query:

string id = dropdwonlist.selectedvalue;          using (sqlconnection sql = new sqlconnection("your connection string"))         {             sqlcommand cmd = new sqlcommand();             string query = @"insert table2(column1)                                values(" + id + ")";             cmd.commandtext = query;             cmd.commandtype = commandtype.text;             cmd.connection = sql;             sql.open();             cmd.executenonquery();             sql.close();         } 

you should way because ensure closing connection after using it.