Change button color using keyboard shortcut C# WPF -

i'm getting c# wpf, , creating simple word processor convert normal text wiki markup. new wpf , having trouble seemingly minuscule, , easy fix.

i have bold button on main form. when pressed need do, turn selected text bold , vice versa when pressed again. bold button changes pretty light blue color when pressed, gray when pressed again. sweet works...

//make bold main method     static bool isbold = false;     public static void boldtext()     {         if (isbold == false)         {              textselection ts = mainwindow.thisform.rtbmain.selection;            mainwindow.thisform.btnbold.background = brushes.lightblue;             if (!ts.isempty)             {                  ts.applypropertyvalue(textelement.fontweightproperty, fontweights.bold);             }             isbold = !isbold;          }         else         {              mainwindow.thisform.btnbold.background = brushes.lightgray;             textselection ts = mainwindow.thisform.rtbmain.selection;             ts.applypropertyvalue(textelement.fontweightproperty, fontweights.normal);             isbold = !isbold;          }      } 

my issue reason when call code above using inputbinding selected text turns bold button color doesn't change... whaaaaa? have created custom command, execute , canexecute commands below:

  public class toolbar    {      //custom command            public static routedcommand boldshortcut = new routedcommand();          //for use keybindings bold command             static bool canexecute = true;             public static void mycommandexecute(object sender, executedroutedeventargs e)             {                 boldtext();                 canexecute = !canexecute;             }             public static void mycommandcanexecute(object sender, canexecuteroutedeventargs e)             {                 e.canexecute = true;             } 

i create keygesture , inputbindings in main form's constructor:

public mainwindow()         {             initializecomponent();             thisform = this;             initializefeatures();              keygesture kg = new keygesture(key.b, modifierkeys.control);             inputbinding ib = new inputbinding(toolbar.boldshortcut, kg);             this.inputbindings.add(ib);         } 

so works reason bold button isn't changing color when use key gesture (ctrl+b). there need in xaml? appreciated , please let me know if unclear or additional info needed. guys!

the command creating (boldshortcut) never being setup anything. routedcommand fires event when activated. there needs command binding somewhere tree listens event , performs logic.

take @ page explanation of how routed commands work:
how to: create routedcommand

additionally, reason text turns bold when press ctrl+b because built-in feature of richtextbox. in fact, richtextbox has whole lot of features can hook toolbar buttons easily. save lot of time learning how use richtextbox before trying reimplement existing features.

here page started: richtextbox overview

(for full list of existing commands can hook things to, see editingcommands class documentation.)