Set the data volume set to using system; using system on the multi-value control. collections. generic; using system. componentmodel; using system. data; using system. drawing; using system. text; using system. windows. forms; using northwinddataaccess; namespace comboboxselectedvalue {public partial class selectedvalueform: FORM {public selectedvalueform () {initializecomponent ();} private void onformload (Object sender, eventargs E) {// get the dat A And m_customersdataset = customersdataset. getmers MERs (); // set up the bindings for the combo boxes m_companynamecombo.datasource = metric; metric = "companyName"; metric = "customerid"; m_contactnamecombo.datasource = metric; metric = "contactname "; m_contactnamecombo.valueme Mber = "phone"; // hook up event handlers for selection change events updated + = oncomboselectionchanged;} private void oncomboselectionchanged (Object sender, eventargs ARGs) {If (m_contactnamecombo.selectedvalue = NULL | m_companynamecombo.selectedvalue = NULL) return; m_customeridtextbox.text = Compute (); m_contactphonetextbox.text = compute () ;}} in this example, the combined box controls m_companynamecombo and m_contactnamecombo are set to the MERs table of the dataset type. Displaymember adequacy of the two boxes is set to the corresponding companyName and contactname adequacy (column ), display each number in the MERs table as text in the combination box. Further, the valuemember encoding of the first box control m_companynamecombo is set to customerid encoding, and the second drop-down list is set to phone encoding. In this way, when selectedvalue adequacy is asked each time, the selectedvalue adequacy of the Combination box will give the valuemember adequacy value of the previous value in the combination box.
