better probing of content for smart hint to decide what state to display. fixes #532

Author: ButchersBoy

MainDemo.Wpf/Snackbars.xaml

@@ -7,6 +7,7 @@
              xmlns:materialDesign="http://materialdesigninxaml.net/winfx/xaml/themes"
              mc:Ignorable="d" 
              d:DesignHeight="300" d:DesignWidth="300">
+    
     <ScrollViewer HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Hidden">
         <Grid Margin="0 0 0 4">
             <Grid.ColumnDefinitions>

MaterialDesignThemes.Wpf/HintProxyFabric.ComboBox.cs

@@ -25,18 +25,26 @@ public object Content
                         return _comboBox.Text;
                     }
 
-                    ComboBoxItem comboBoxItem = _comboBox.SelectedItem as ComboBoxItem;
+                    var comboBoxItem = _comboBox.SelectedItem as ComboBoxItem;
                     return comboBoxItem != null 
                         ? comboBoxItem.Content
                         : _comboBox.SelectedItem;
                 }
             }
 
             public bool IsLoaded => _comboBox.IsLoaded;
-            public bool IsVisible => _comboBox.IsVisible;
+
+            public bool IsVisible => _comboBox.IsVisible;            
+
+            public bool IsEmpty()
+            {
+                return string.IsNullOrWhiteSpace(_comboBox.Text);
+            }
 
             public event EventHandler ContentChanged;
+
             public event EventHandler IsVisibleChanged;
+
             public event EventHandler Loaded;
 
             public ComboBoxHintProxy(ComboBox comboBox)

MaterialDesignThemes.Wpf/HintProxyFabric.PasswordBox.cs

@@ -9,8 +9,12 @@ private sealed class PasswordBoxHintProxy : IHintProxy
         {
             private readonly PasswordBox _passwordBox;
 
+            public bool IsEmpty() => string.IsNullOrWhiteSpace(_passwordBox.Password);          
+
             public object Content => _passwordBox.Password;
+
             public bool IsLoaded => _passwordBox.IsLoaded;
+
             public bool IsVisible => _passwordBox.IsVisible;
 
             public event EventHandler ContentChanged;

MaterialDesignThemes.Wpf/HintProxyFabric.TextBox.cs

@@ -11,9 +11,13 @@ private sealed class TextBoxHintProxy : IHintProxy
             private readonly TextBox _textBox;
 
             public object Content => _textBox.Text;
+
             public bool IsLoaded => _textBox.IsLoaded;
+
             public bool IsVisible => _textBox.IsVisible;
 
+            public bool IsEmpty() => string.IsNullOrWhiteSpace(_textBox.Text);
+
             public event EventHandler ContentChanged;
             public event EventHandler IsVisibleChanged;
             public event EventHandler Loaded;

MaterialDesignThemes.Wpf/IHintProxy.cs

@@ -14,6 +14,14 @@ namespace MaterialDesignThemes.Wpf
     /// </summary>
     public interface IHintProxy : IDisposable
     {
+        /// <summary>
+        /// Checks to see if the targetted control can be deemed as logically 
+        /// empty, even if not null, affecting the current hint display.
+        /// </summary>
+        /// <returns></returns>
+        bool IsEmpty();
+
+        [Obsolete]
         object Content { get; }
 
         bool IsLoaded { get; }

MaterialDesignThemes.Wpf/SmartHint.cs

@@ -150,7 +150,7 @@ private static void HintProxyPropertyChangedCallback(DependencyObject dependency
 
         protected virtual void OnHintProxyContentChanged(object sender, EventArgs e)
         {
-            IsContentNullOrEmpty = string.IsNullOrEmpty((HintProxy.Content ?? "").ToString());
+            IsContentNullOrEmpty = HintProxy.IsEmpty();
 
             if (HintProxy.IsLoaded)
             {
@@ -182,7 +182,7 @@ private void RefreshState(bool useTransitions)
 
             var action = new Action(() =>
             {
-                var state = String.IsNullOrEmpty((proxy.Content ?? String.Empty).ToString())
+                var state = proxy.IsEmpty()
                     ? ContentEmptyName
                     : ContentNotEmptyName;
 
@@ -198,5 +198,7 @@ private void RefreshState(bool useTransitions)
                 Dispatcher.BeginInvoke(action);
             }
         }
+
+
     }
 }