From 1517b45d673183868db2883b916cdee87f06cc79 Mon Sep 17 00:00:00 2001
From: nishy2000 <github@nishy.net>
Date: Wed, 23 Sep 2015 23:26:09 +0900
Subject: [PATCH] ToggleButtonHelper.OnIsCheckedChanged()  accepts  type of
 "bool?".

---
 Fluent/Helpers/ToggleButtonHelper.cs   |  4 ++--
 FluentTest/TestContent.xaml            |  2 +-
 FluentTest/ViewModels/MainViewModel.cs | 14 ++++++++++++++
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/Fluent/Helpers/ToggleButtonHelper.cs b/Fluent/Helpers/ToggleButtonHelper.cs
index 52f9d27ab..ab911d899 100644
--- a/Fluent/Helpers/ToggleButtonHelper.cs
+++ b/Fluent/Helpers/ToggleButtonHelper.cs
@@ -80,11 +80,11 @@ public static object CoerceIsChecked(DependencyObject d, object basevalue)
         /// </summary>
         public static void OnIsCheckedChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
         {
-            var newValue = (bool)e.NewValue;
+            var newValue = (bool?)e.NewValue;
             var button = (IToggleButton)d;
 
             // Uncheck other toggle buttons
-            if (!newValue || button.GroupName == null)
+            if (!newValue.HasValue || !newValue.Value || button.GroupName == null)
             {
                 return;
             }
diff --git a/FluentTest/TestContent.xaml b/FluentTest/TestContent.xaml
index 2422f1fb8..9e93522e7 100644
--- a/FluentTest/TestContent.xaml
+++ b/FluentTest/TestContent.xaml
@@ -1120,7 +1120,7 @@
                     <Fluent:ToggleButton Header="Toggle 2"
                                          GroupName="Group1" />
                     <Fluent:ToggleButton Header="Toggle 3"
-                                         GroupName="Group1" />
+                                         GroupName="Group1" IsChecked="{Binding Path=IsCheckedToggleButton3}"/>
                 </Fluent:RibbonGroupBox>
 
                 <Fluent:RibbonGroupBox>
diff --git a/FluentTest/ViewModels/MainViewModel.cs b/FluentTest/ViewModels/MainViewModel.cs
index fd03e0331..98b17aec6 100644
--- a/FluentTest/ViewModels/MainViewModel.cs
+++ b/FluentTest/ViewModels/MainViewModel.cs
@@ -22,6 +22,7 @@ public class MainViewModel : ViewModel
 		private double zoom;
 		private ICommand testCommand;
         private string[] manyItems;
+        private bool? isCheckedToggleButton3;
 
         public MainViewModel()
         {
@@ -133,6 +134,19 @@ public string[] ManyItems
             get { return this.manyItems ?? (this.manyItems = this.GenerateStrings(5000)); }
         }
 
+        public bool? IsCheckedToggleButton3
+        {
+            get { return this.isCheckedToggleButton3; }
+            set
+            {
+                if (this.isCheckedToggleButton3 != value)
+                {
+                    this.isCheckedToggleButton3 = value;
+                    this.OnPropertyChanged("ToggleButton3IsChecked");
+                }
+            }
+        }
+
         private string[] GenerateStrings(int count)
         {
             return Enumerable.Repeat("Test", count).ToArray();