c# - How to use variables from another class -

alright, here go. kinda new programming , c#, i'm learning john sharp's visual c#: step step book. (i wonder if dude's last name sharp)

anyway, i'm trying create application me transpose note. it's windows forms app , i'm using 2 classes: form1.cs code happens , vars.cs variables stored.

my problem want use string vars.notechosen , define comboboxnote's selected item (e.g. c). whenever this, however, when execute vars.notechosen = combonote.selectedtext; "object reference not set instance of object." error. ideas? (combonote combobox)

this vars.cs

namespace transposer {     class vars     {         public static bool rbtransposeup = true;         public static string notechosen = ""; //         public static string totranspose = ""; //          public static int note = 0;         public static string boxresulttext = note.tostring();     } } 

and part of form1.cs

namespace transposer {     public partial class transposer : form     {         public transposer()         {             vars.notechosen = combonote.selectedtext;             vars.totranspose = combonote.text;             initializecomponent();         } 

...

what doing wrong?

move lines after call initializecomponent(); it's call creating combonote object.

that is

    public transposer()     {         initializecomponent(); // constructs combonote         vars.notechosen = combonote.selectedtext;         vars.totranspose = combonote.text;     }