winforms - Add items to combobox with multiple values C# -

currently have combobox 3 hard coded items. each item carries 2 values. i'm using switch case statement values each item depending on item selected.

switch(combobox.selectedindex) {     case 0: // item 1 in combobox         = 100;         b = 0.1;         break;     case 1: // item 2 in combobox         = 300;         b = 0.5;         break;     //and on.... } 

i'm trying add feature allow user add more items combobox inputted , b values. how able dynamically add case statements , define values under each case condition? i've had @ using datatable instead don't know how multiple valuemembers out of datatable when 1 item selected.

also, save user added items , it's corresponding values .dat file. when program re-opened able load list of items added user file. considered using streamwriter , readline i'm unsure how done.

you can use binding on combobox using datasource. combobox can bound other things primitive values (string/int/hardcoded values). make small class represents values setting in switch statement, , use displaymember property should visible in combobox.

an example of such basic class be

public class datastructure {     public double { get; set; }      public int b { get; set; }      public string title { get; set; } } 

since talking users adding values combobox dynamically, use bindinglist contains separate classes, bindinglist protected field inside class, add new datastructure when user adds one, , automatically updates combobox new value added.

the setup of combobox, can done in either form_load, or in form constructor (after initializecomponent() call), such:

// form public partial class form1 : form {     // property contains items shown in combobox     protected ilist<datastructure> dataitems = new bindinglist<datastructure>();     // way keep selected reference not have ask combobox, gets updated on selection changed events     protected datastructure selecteddatastructure = null;      public form1()     {         initializecomponent();         // create default values here         dataitems.add(new datastructure { = 0.5, b = 100, title = "some value" });         dataitems.add(new datastructure { = 0.75, b = 100, title = "more value" });         dataitems.add(new datastructure { = 0.95, b = 100, title = "even more value" });         // assign dataitems combobox datasource         combobox1.datasource = dataitems;         // combobox should show in dropdown         combobox1.displaymember = "title";         // set list only, no typing         combobox1.dropdownstyle = comboboxstyle.dropdownlist;         // register event triggers each time selection changes         combobox1.selectedindexchanged += combobox1_selectedindexchanged;     }      // method add items dataitems (and automatically combobox bindingcontext)     private void add(double a, int b, string title)     {         dataitems.add(new datastructure { = a, b = b, title = title });     }      // when value changes, update selecteddatastructure field     private void combobox1_selectedindexchanged(object sender, eventargs e)     {         combobox combo = sender combobox;         if (combo == null)         {             return;         }         selecteddatastructure = combo.selecteditem datastructure;         if (selecteddatastructure == null)         {             messagebox.show("you didn't select @ moment");         }         else         {             messagebox.show(string.format("you selected {0} = {1:n2}, b = {2}", selecteddatastructure.title, selecteddatastructure.a, selecteddatastructure.b));         }     }      // add items on button click     private void addcomboboxitembutton_click(object sender, eventargs e)     {         string title = textbox1.text;         if (string.isnullorwhitespace(title))         {             messagebox.show("a title required!");             return;         }         random random = new random();         double = random.nextdouble();         int b = random.next();         add(a, b, title);         textbox1.text = string.empty;     } } 

like this, have selected item @ hand, can request values properties of selected, , don't have worry syncing combobox items visible