Fix regressions with NumberBox HeaderPresenter behavior (microsoft/mi…

…crosoft-ui-xaml#2148)
Kinnara · Apr 30, 2020 · 929b4ae · 929b4ae
1 parent 292f7ce
commit 929b4ae
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Showing 8 changed files with 298 additions and 217 deletions.
diff --git a/ModernWpf.Controls/NumberBox/NumberBox.cs b/ModernWpf.Controls/NumberBox/NumberBox.cs
@@ -32,6 +32,7 @@ public NumberBoxValueChangedEventArgs(double oldValue, double newValue)
     [TemplatePart(Name = c_numberBoxPopupUpButtonName, Type = typeof(RepeatButton))]
     public partial class NumberBox : Control
     {
+        const string c_numberBoxHeaderName = "HeaderContentPresenter";
         const string c_numberBoxDownButtonName = "DownSpinButton";
         const string c_numberBoxUpButtonName = "UpSpinButton";
         const string c_numberBoxTextBoxName = "InputBox";
@@ -98,6 +99,8 @@ public override void OnApplyTemplate()
                 }
             }
 
+            UpdateHeaderPresenterState();
+
             m_textBox = GetTextBox();
             TextBox GetTextBox()
             {
@@ -285,6 +288,16 @@ private void UpdateValueToText()
             }
         }
 
+        private void OnHeaderPropertyChanged(DependencyPropertyChangedEventArgs args)
+        {
+            UpdateHeaderPresenterState();
+        }
+
+        private void OnHeaderTemplatePropertyChanged(DependencyPropertyChangedEventArgs args)
+        {
+            UpdateHeaderPresenterState();
+        }
+
         private void OnValidationModePropertyChanged(DependencyPropertyChangedEventArgs args)
         {
             ValidateInput();
@@ -590,12 +603,57 @@ private bool IsInBounds(double value)
             return value >= Minimum && value <= Maximum;
         }
 
+        private void UpdateHeaderPresenterState()
+        {
+            bool shouldShowHeader = false;
+
+            // Load header presenter as late as possible
+
+            // To enable lightweight styling, collapse header presenter if there is no header specified
+            if (Header is { } header)
+            {
+                // Check if header is string or not
+                if (header is string headerAsString)
+                {
+                    if (!string.IsNullOrEmpty(headerAsString))
+                    {
+                        // Header is not empty string
+                        shouldShowHeader = true;
+                    }
+                }
+                else
+                {
+                    // Header is not a string, so let's show header presenter
+                    shouldShowHeader = true;
+                }
+            }
+            if (HeaderTemplate is { } headerTemplate)
+            {
+                shouldShowHeader = true;
+            }
+
+            if (shouldShowHeader && m_headerPresenter == null)
+            {
+                if (GetTemplateChild(c_numberBoxHeaderName) is ContentPresenter headerPresenter)
+                {
+                    // Set presenter to enable lightweight styling of the headers margin
+                    m_headerPresenter = headerPresenter;
+                }
+            }
+
+            if (m_headerPresenter != null)
+            {
+                m_headerPresenter.Visibility = shouldShowHeader ? Visibility.Visible : Visibility.Collapsed;
+            }
+        }
+
         bool m_valueUpdating = false;
         bool m_textUpdating = false;
 
         DefaultNumberRounder m_displayRounder = new DefaultNumberRounder();
 
         TextBox m_textBox;
+        ContentPresenter m_headerPresenter;
         Popup m_popup;
         PopupRepositionHelper m_popupRepositionHelper;
     }

diff --git a/ModernWpf.Controls/NumberBox/NumberBox.properties.cs b/ModernWpf.Controls/NumberBox/NumberBox.properties.cs
@@ -142,27 +142,41 @@ private static void OnTextPropertyChanged(DependencyObject sender, DependencyPro
         #region Header
 
         public static readonly DependencyProperty HeaderProperty =
-            ControlHelper.HeaderProperty.AddOwner(typeof(NumberBox));
+            ControlHelper.HeaderProperty.AddOwner(
+                typeof(NumberBox),
+                new FrameworkPropertyMetadata(OnHeaderPropertyChanged));
 
         public object Header
         {
             get => GetValue(HeaderProperty);
             set => SetValue(HeaderProperty, value);
         }
 
+        private static void OnHeaderPropertyChanged(DependencyObject sender, DependencyPropertyChangedEventArgs args)
+        {
+            ((NumberBox)sender).OnHeaderPropertyChanged(args);
+        }
+
         #endregion
 
         #region HeaderTemplate
 
         public static readonly DependencyProperty HeaderTemplateProperty =
-            ControlHelper.HeaderTemplateProperty.AddOwner(typeof(NumberBox));
+            ControlHelper.HeaderTemplateProperty.AddOwner(
+                typeof(NumberBox),
+                new FrameworkPropertyMetadata(OnHeaderTemplatePropertyChanged));
 
         public DataTemplate HeaderTemplate
         {
             get => (DataTemplate)GetValue(HeaderTemplateProperty);
             set => SetValue(HeaderTemplateProperty, value);
         }
 
+        private static void OnHeaderTemplatePropertyChanged(DependencyObject sender, DependencyPropertyChangedEventArgs args)
+        {
+            ((NumberBox)sender).OnHeaderTemplatePropertyChanged(args);
+        }
+
         #endregion
 
         #region PlaceholderText

diff --git a/ModernWpf.Controls/NumberBox/NumberBox.xaml b/ModernWpf.Controls/NumberBox/NumberBox.xaml
@@ -324,7 +324,7 @@
                             Margin="{DynamicResource TextBoxTopHeaderMargin}"
                             TextWrapping="Wrap"
                             VerticalAlignment="Top"
-                            Visibility="{TemplateBinding ui:ControlHelper.HeaderVisibility}"
+                            Visibility="Collapsed"
                             SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
 
                         <TextBox