C#下拉框调用数据库数据

1、c#做下来框调用数据库数据代码：using system;using system.collections.generic;using system.componentmodel;using system.data;using system.drawing;using system.linq;using system.text;using system.windows.forms;using system.data.oledb;namespace 省市查询 public partial class form1 : form public form1() initializecomponent(

2、); private void form1_load(object sender, eventargs e) using (oledbconnection conn = new oledbconnection(provider=microsoft.jet.oledb.4.0;data source=e:dbcity.mdb) conn.open(); string sql=null; using (oledbcommand cmd = new oledbcommand(sql, conn) cmd.commandtext=select * from promary; using (oledbd

3、atareader read = cmd.executereader() while (read.read() sheng s=new sheng(); s.id = read.getint32(read.getordinal(proid); s.name = read.getstring(read.getordinal(proname); combobox1.items.add(s); private void combobox1_selectedindexchanged(object sender, eventargs e) sheng s = (sheng)combobox1.selec

4、teditem; using (oledbconnection conn = new oledbconnection(provider=microsoft.jet.oledb.4.0;data source=e:dbcity.mdb) conn.open(); string sql = null; using (oledbcommand cmd = new oledbcommand(sql, conn) cmd.commandtext = select * from t_city where proid=+s.id; using (oledbdatareader read = cmd.executereader() combobox2.items.clear(); while (read.read() s.name = read.getstring(read.getordinal(city); combobox2.items.add(