fix floating hint issue on returning to a screen fixes #193

Author: ButchersBoy

MaterialDesignThemes.Wpf/PasswordFieldAssist.cs

@@ -17,14 +17,14 @@ private static void ManagedPropertyChangedCallback(DependencyObject dependencyOb
             if (passwordBox != null)
             {
                 passwordBox.PasswordChanged -= PasswordBoxOnPasswordChanged;
+                passwordBox.Loaded -= PasswordBoxOnPasswordChanged;
             }
 
             passwordBox = dependencyPropertyChangedEventArgs.NewValue as PasswordBox;
             if (passwordBox != null)
             {
                 passwordBox.PasswordChanged += PasswordBoxOnPasswordChanged;
-                // call listener immediately, maybe passwordbox was not empty
-                PasswordBoxOnPasswordChanged(passwordBox, new RoutedEventArgs());
+                passwordBox.Loaded += PasswordBoxOnPasswordChanged;
             }
         }
 
@@ -57,34 +57,57 @@ private static void ConfigureHint(PasswordBox passwordBox)
             passwordBox.SetValue(HintVisibilityProperty, passwordBox.SecurePassword.Length == 0 ? Visibility.Visible : Visibility.Hidden);
         }
 
+        /// <summary>
+        /// Framework use only.
+        /// </summary>
         public static readonly DependencyProperty HintVisibilityProperty = DependencyProperty.RegisterAttached(
             "HintVisibility", typeof(Visibility), typeof(PasswordFieldAssist), new PropertyMetadata(default(Visibility)));
 
+        /// <summary>
+        /// Framework use only.
+        /// </summary>
         public static void SetHintVisibility(DependencyObject element, Visibility value)
         {
             element.SetValue(HintVisibilityProperty, value);
         }
 
+        /// <summary>
+        /// Framework use only.
+        /// </summary>
         public static Visibility GetHintVisibility(DependencyObject element)
         {
             return (Visibility)element.GetValue(HintVisibilityProperty);
         }
 
+        /// <summary>
+        /// Framework use only.
+        /// </summary>
+        /// <param name="element"></param>
+        /// <param name="value"></param>
         public static void SetManaged(DependencyObject element, PasswordBox value)
         {
             element.SetValue(ManagedProperty, value);
         }
 
+        /// <summary>
+        /// Framework use only.
+        /// </summary>
         public static PasswordBox GetManaged(DependencyObject element)
         {
             return (PasswordBox)element.GetValue(ManagedProperty);
         }
 
+        /// <summary>
+        /// Framework use only.
+        /// </summary>
         private static void SetIsNullOrEmpty(DependencyObject element, bool value)
         {
             element.SetValue(IsNullOrEmptyPropertyKey, value);
         }
 
+        /// <summary>
+        /// Framework use only.
+        /// </summary>
         public static bool GetIsNullOrEmpty(DependencyObject element)
         {
             return (bool)element.GetValue(IsNullOrEmptyProperty);

MaterialDesignThemes.Wpf/TextFieldAssist.cs

@@ -52,6 +52,12 @@ public static class TextFieldAssist
         private static readonly DependencyProperty IsNullOrEmptyProperty =
             IsNullOrEmptyPropertyKey.DependencyProperty;
 
+        /// <summary>
+        /// Framework use only.
+        /// </summary>
+        public static readonly DependencyProperty ManagedProperty = DependencyProperty.RegisterAttached(
+            "Managed", typeof(TextBox), typeof(TextFieldAssist), new PropertyMetadata(default(TextBox), ManagedPropertyChangedCallback));        
+
         #endregion
 
         #region Public Methods and Operators
@@ -132,6 +138,24 @@ public static string GetText(DependencyObject element)
             return (string)element.GetValue(TextProperty);
         }
 
+        /// <summary>
+        /// Framework use only.
+        /// </summary>
+        public static void SetManaged(DependencyObject element, TextBox value)
+        {
+            element.SetValue(ManagedProperty, value);
+        }
+
+        /// <summary>
+        /// Framework use only.
+        /// </summary>
+        /// <param name="element"></param>
+        /// <returns></returns>
+        public static TextBox GetManaged(DependencyObject element)
+        {
+            return (TextBox) element.GetValue(ManagedProperty);
+        }
+
         #endregion
 
         #region Methods
@@ -199,11 +223,44 @@ private static void TextPropertyChangedCallback(DependencyObject dependencyObjec
             else
             {
                 frameworkElement.Loaded += (sender, args) => VisualStateManager.GoToState(frameworkElement, state, false);
+                frameworkElement.IsVisibleChanged += (sender, args) => VisualStateManager.GoToState(frameworkElement, state, true);
             }
 
             SetIsNullOrEmpty(dependencyObject, string.IsNullOrEmpty((dependencyPropertyChangedEventArgs.NewValue ?? "").ToString()));
         }
 
+        private static void ManagedPropertyChangedCallback(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs dependencyPropertyChangedEventArgs)
+        {
+            var textBox = dependencyPropertyChangedEventArgs.OldValue as TextBox;
+            if (textBox != null)
+            {
+                textBox.IsVisibleChanged -= ManagedTextBoxOnIsVisibleChanged;                
+            }
+
+            textBox = dependencyPropertyChangedEventArgs.NewValue as TextBox;
+            if (textBox != null)
+            {
+                textBox.IsVisibleChanged += ManagedTextBoxOnIsVisibleChanged;                
+            }
+        }
+
+        private static void ManagedTextBoxOnIsVisibleChanged(object sender, DependencyPropertyChangedEventArgs dependencyPropertyChangedEventArgs)
+        {
+            var textBox = (TextBox)sender;
+
+            if (!textBox.IsVisible) return;
+
+            var state = string.IsNullOrEmpty(textBox.Text)
+                ? "MaterialDesignStateTextEmpty"
+                : "MaterialDesignStateTextNotEmpty";
+
+            //yep, had to invoke post this to trigger refresh
+            textBox.Dispatcher.BeginInvoke(new Action(() =>
+            {
+                VisualStateManager.GoToState(textBox, state, false);
+            }));
+        }
+
         private static void SetIsNullOrEmpty(DependencyObject element, bool value)
         {
             element.SetValue(IsNullOrEmptyPropertyKey, value);

MaterialDesignThemes.Wpf/Themes/MaterialDesignTheme.TextBox.xaml

@@ -113,6 +113,7 @@
 
     <Style x:Key="MaterialDesignFloatingHintTextBox" TargetType="{x:Type TextBox}" BasedOn="{StaticResource MaterialDesignTextBox}">
         <Setter Property="wpf:TextFieldAssist.Text" Value="{Binding RelativeSource={RelativeSource Self}, Path=Text}" />
+        <Setter Property="wpf:TextFieldAssist.Managed" Value="{Binding RelativeSource={RelativeSource Self}}" />
         <Setter Property="Template">
             <Setter.Value>
                 <ControlTemplate TargetType="TextBox">