invalidate command manager to reset button states on dialogs. issue #445

Author: ButchersBoy

MaterialDesignThemes.Wpf/DialogHost.cs

@@ -265,7 +265,7 @@ private static void IsOpenPropertyChangedCallback(DependencyObject dependencyObj
                 // Don't attempt to Invoke if _restoreFocusDialogClose hasn't been assigned yet. Can occur
                 // if the MainWindow has started up minimized. Even when Show() has been called, this doesn't
                 // seem to have been set.
-                dialogHost.Dispatcher.InvokeAsync(() => dialogHost._restoreFocusDialogClose?.Focus(), DispatcherPriority.Input);
+                dialogHost.Dispatcher.InvokeAsync(() => dialogHost._restoreFocusDialogClose?.Focus(), DispatcherPriority.Input);                
 
                 return;
             }
@@ -289,6 +289,7 @@ private static void IsOpenPropertyChangedCallback(DependencyObject dependencyObj
             dialogHost.Dispatcher.BeginInvoke(DispatcherPriority.Background, new Action(() =>
             {
                 var child = dialogHost.FocusPopup();
+                CommandManager.InvalidateRequerySuggested();
 
                 //https://github.com/ButchersBoy/MaterialDesignInXamlToolkit/issues/187
                 //totally not happy about this, but on immediate validation we can get some weird looking stuff...give WPF a kick to refresh...

MaterialDesignThemes.Wpf/DialogSession.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Windows.Input;
 using System.Windows.Threading;
 
 namespace MaterialDesignThemes.Wpf
@@ -40,7 +41,11 @@ public void UpdateContent(object content)
 
             _owner.AssertTargetableContent();
             _owner.DialogContent = content;
-            _owner.Dispatcher.BeginInvoke(DispatcherPriority.Background, new Action(() => _owner.FocusPopup()));            
+            _owner.Dispatcher.BeginInvoke(DispatcherPriority.Background, new Action(() =>
+            {
+                _owner.FocusPopup();
+                CommandManager.InvalidateRequerySuggested();
+            }));            
         }
 
         /// <summary>