Content update - Property value inheritance (user story 1878471) (#1261)

* Add article, code, toc, and redirects * Resolve vb project issues * Update .openpublishing.redirection.json Co-authored-by: Andy (Steve) De George <[email protected]>
2026-09-08 23:43:29 +02:00 · 2022-01-05 15:16:55 -08:00
parent cf371fba4c
commit e990fbc9a6
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+<Application x:Class="Application"
+             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             StartupUri="MainWindow.xaml">
+    <Application.Resources>
+         
+    </Application.Resources>
+</Application>
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+Class Application
+
+    ' Application-level events, such as Startup, Exit, and DispatcherUnhandledException
+    ' can be handled in this file.
+
+End Class
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+'The ThemeInfo attribute describes where any theme specific and generic resource dictionaries can be found.
+'1st parameter: where theme specific resource dictionaries are located
+'(used if a resource is not found in the page,
+' or application resource dictionaries)
+
+'2nd parameter: where the generic resource dictionary is located
+'(used if a resource is not found in the page,
+'app, and any theme specific resource dictionaries)
+<Assembly: ThemeInfo(ResourceDictionaryLocation.None, ResourceDictionaryLocation.SourceAssembly)>
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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>WinExe</OutputType>
+    <TargetFramework>net6.0-windows</TargetFramework>
+    <UseWPF>true</UseWPF>
+    <RootNamespace>CodeSampleVb</RootNamespace>
+    <NeutralLanguage>en-US</NeutralLanguage>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Import Include="System.Windows" />
+    <Import Include="System.Windows.Controls" />
+    <Import Include="System.Windows.Data" />
+    <Import Include="System.Windows.Documents" />
+    <Import Include="System.Windows.Input" />
+    <Import Include="System.Windows.Media" />
+    <Import Include="System.Windows.Media.Imaging" />
+    <Import Include="System.Windows.Navigation" />
+    <Import Include="System.Windows.Shapes" />
+  </ItemGroup>
+
+</Project>
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+<Window x:Class="CodeSampleVb.MainWindow"
+    xmlns:local="clr-namespace:CodeSampleVb.CodeSampleVb"
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        Title="Property value inheritance" Height="200" Width="400" Background="Yellow">
+
+    <Grid>
+        <Grid.ColumnDefinitions>
+            <ColumnDefinition Width="260*"></ColumnDefinition>
+            <ColumnDefinition Width="260*"></ColumnDefinition>
+        </Grid.ColumnDefinitions>
+
+        <!--<XamlElementTree>-->
+        <Canvas x:Name="canvas1" Grid.Column="0" Margin="20" Background="Orange" AllowDrop="True">
+            <StackPanel x:Name="stackPanel1" Margin="20" Background="Green">
+                <Label x:Name="label1" Margin="20" Height="40" Width="40" Background="Blue"/>
+            </StackPanel>
+        </Canvas>
+        <!--</XamlElementTree>-->
+
+        <local:Canvas_AllowDropInheritDisabled Grid.Column="1" Margin="20" Background="Orange" AllowDrop="True">
+            <StackPanel Name="stackPanel11" Margin="20" Background="Green">
+                <Label Name="label11" Margin="20" Height="40" Width="40" Background="Blue"/>
+            </StackPanel>
+        </local:Canvas_AllowDropInheritDisabled>
+
+    </Grid>
+
+</Window>
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+Namespace CodeSampleVb
+    Partial Public Class MainWindow
+        Inherits Window
+
+        Public Sub New()
+            InitializeComponent()
+
+            ' Code tests.
+            TestAllowDropInheritanceInXaml()
+            TestAllowDropInheritanceInCode()
+            TestIsTransparentInheritanceInCode()
+            TestDependencyPropertyWrapper()
+        End Sub
+
+        Private Sub TestAllowDropInheritanceInXaml()
+
+            ' Test enabled property value inheritance.
+            Dim fpm1 As FrameworkPropertyMetadata =
+                CType(AllowDropProperty.
+                GetMetadata(GetType(Canvas)), FrameworkPropertyMetadata)
+            Debug.Assert(fpm1.[Inherits] = True)
+            Debug.Assert(canvas1.AllowDrop = True)
+            Debug.Assert(stackPanel1.AllowDrop = True)
+            Debug.Assert(label1.AllowDrop = True)
+
+            ' Test disabled property value inheritance.
+            Dim fpm11 As FrameworkPropertyMetadata =
+                CType(AllowDropProperty.
+                GetMetadata(GetType(Canvas_AllowDropInheritDisabled)), FrameworkPropertyMetadata)
+            Debug.Assert(fpm11.[Inherits] = False)
+            ' Debug.Assert(canvas11.AllowDrop = True)
+            Debug.Assert(stackPanel11.AllowDrop = False)
+            Debug.Assert(label11.AllowDrop = False)
+        End Sub
+
+        Private Shared Sub TestAllowDropInheritanceInCode()
+
+            '<CodeElementTree>
+            Dim canvas2 As New Canvas With {
+                .AllowDrop = True
+            }
+            Dim stackPanel2 As New StackPanel()
+            Dim label2 As New Label()
+            canvas2.Children.Add(stackPanel2)
+            stackPanel2.Children.Add(label2)
+            '</CodeElementTree>
+
+            ' Test enabled property value inheritance.
+            Dim fpm2 As FrameworkPropertyMetadata =
+                CType(AllowDropProperty.
+                GetMetadata(GetType(Canvas)), FrameworkPropertyMetadata)
+            Debug.Assert(fpm2.[Inherits] = True)
+            Debug.Assert(canvas2.AllowDrop = True)
+            Debug.Assert(stackPanel2.AllowDrop = True)
+            Debug.Assert(label2.AllowDrop = True)
+
+            ' Test disabled property value inheritance.
+            Dim canvas3 As New Canvas_AllowDropInheritDisabled With {
+                .AllowDrop = True
+            }
+            Dim stackPanel3 As New StackPanel()
+            Dim label3 As New Label()
+            canvas3.Children.Add(stackPanel3)
+            stackPanel3.Children.Add(label3)
+            Dim fpm3 As FrameworkPropertyMetadata =
+                CType(AllowDropProperty.
+                GetMetadata(GetType(Canvas_AllowDropInheritDisabled)), FrameworkPropertyMetadata)
+            Debug.Assert(fpm3.[Inherits] = False)
+            Debug.Assert(canvas3.AllowDrop = True)
+            Debug.Assert(stackPanel3.AllowDrop = False)
+            Debug.Assert(label3.AllowDrop = False)
+
+        End Sub
+
+        Private Shared Sub TestIsTransparentInheritanceInCode()
+
+            ' Test enabled property value inheritance.
+            Dim myCanvas1 As New Canvas_IsTransparentInheritEnabled With {
+                .IsTransparent = True
+            }
+            Dim myCanvas2 As New Canvas_IsTransparentInheritEnabled2()
+            Dim myCanvas3 As New Canvas_IsTransparentInheritEnabled3()
+            myCanvas1.Children.Add(myCanvas2)
+            myCanvas2.Children.Add(myCanvas3)
+            Dim fpm1 As FrameworkPropertyMetadata =
+                CType(Canvas_IsTransparentInheritEnabled.IsTransparentProperty.
+                GetMetadata(GetType(Canvas_IsTransparentInheritEnabled)), FrameworkPropertyMetadata)
+            Debug.Assert(fpm1.[Inherits] = True)
+            Debug.Assert(myCanvas1.IsTransparent = True)
+            Debug.Assert(myCanvas2.IsTransparent = True)
+            Debug.Assert(myCanvas3.IsTransparent = True)
+
+            ' Test disabled property value inheritance.
+            Dim myCanvas4 As New Canvas_IsTransparentInheritDisabled With {
+                .IsTransparent = True
+            }
+            Dim myCanvas5 As New Canvas_IsTransparentInheritDisabled2()
+            Dim myCanvas6 As New Canvas_IsTransparentInheritDisabled3()
+            myCanvas4.Children.Add(myCanvas5)
+            myCanvas5.Children.Add(myCanvas6)
+            Dim fpm2 As FrameworkPropertyMetadata =
+                CType(Canvas_IsTransparentInheritDisabled.IsTransparentProperty.
+                GetMetadata(GetType(Canvas_IsTransparentInheritDisabled)), FrameworkPropertyMetadata)
+            Debug.Assert(fpm2.[Inherits] = False)
+            Debug.Assert(myCanvas4.IsTransparent = True)
+            Debug.Assert(myCanvas5.IsTransparent = False)
+            Debug.Assert(myCanvas6.IsTransparent = False)
+
+        End Sub
+
+        Private Shared Sub TestDependencyPropertyWrapper()
+
+            ' Test Canvas_IsTransparentInheritEnabled.
+            Dim myCanvas1 As New Canvas_IsTransparentInheritEnabled()
+            Dim myCanvas2 As New Canvas_IsTransparentInheritEnabled2()
+            Dim myCanvas3 As New Canvas_IsTransparentInheritEnabled3()
+            ' Test property wrapper.
+            myCanvas1.IsTransparent = True
+            myCanvas2.IsTransparent = False
+            myCanvas3.IsTransparent = True
+            Debug.Assert(myCanvas1.IsTransparent = True)
+            Debug.Assert(myCanvas2.IsTransparent = False)
+            Debug.Assert(myCanvas3.IsTransparent = True)
+            ' Test individual get/set accessors.
+            Canvas_IsTransparentInheritEnabled.SetIsTransparent(myCanvas1, False)
+            Canvas_IsTransparentInheritEnabled.SetIsTransparent(myCanvas2, True)
+            Canvas_IsTransparentInheritEnabled.SetIsTransparent(myCanvas3, False)
+            Debug.Assert(Canvas_IsTransparentInheritEnabled.GetIsTransparent(myCanvas1) = False)
+            Debug.Assert(Canvas_IsTransparentInheritEnabled.GetIsTransparent(myCanvas2) = True)
+            Debug.Assert(Canvas_IsTransparentInheritEnabled.GetIsTransparent(myCanvas3) = False)
+
+            ' Test Canvas_IsTransparentInheritDisabled.
+            Dim myCanvas4 As New Canvas_IsTransparentInheritDisabled()
+            Dim myCanvas5 As New Canvas_IsTransparentInheritDisabled2()
+            Dim myCanvas6 As New Canvas_IsTransparentInheritDisabled3()
+            ' Test property wrapper.
+            myCanvas4.IsTransparent = True
+            myCanvas5.IsTransparent = False
+            myCanvas6.IsTransparent = True
+            Debug.Assert(myCanvas4.IsTransparent = True)
+            Debug.Assert(myCanvas5.IsTransparent = False)
+            Debug.Assert(myCanvas6.IsTransparent = True)
+            ' Test individual get/set accessors.
+            Canvas_IsTransparentInheritDisabled.SetIsTransparent(myCanvas4, False)
+            Canvas_IsTransparentInheritDisabled.SetIsTransparent(myCanvas5, True)
+            Canvas_IsTransparentInheritDisabled.SetIsTransparent(myCanvas6, False)
+            Debug.Assert(Canvas_IsTransparentInheritDisabled.GetIsTransparent(myCanvas4) = False)
+            Debug.Assert(Canvas_IsTransparentInheritDisabled.GetIsTransparent(myCanvas5) = True)
+            Debug.Assert(Canvas_IsTransparentInheritDisabled.GetIsTransparent(myCanvas6) = False)
+
+        End Sub
+    End Class
+
+    Public Class Canvas_AllowDropInheritDisabled
+        Inherits Canvas
+        Shared Sub New()
+            ' Disable property value inheritance in a new property metadata object.
+            Dim frameworkPropertyMetadata As New FrameworkPropertyMetadata With {
+                .Inherits = False
+            }
+            ' Override existing property metadata.
+            AllowDropProperty.OverrideMetadata(GetType(Canvas_AllowDropInheritDisabled), frameworkPropertyMetadata)
+        End Sub
+    End Class
+
+    '<RegisterAttachedPropertyWithValueInheritance>
+    Public Class Canvas_IsTransparentInheritEnabled
+        Inherits Canvas
+
+        ' Register an attached dependency property with the specified
+        ' property name, property type, owner type, and property metadata
+        ' (default value is 'false' and property value inheritance is enabled).
+        Public Shared ReadOnly IsTransparentProperty As DependencyProperty =
+            DependencyProperty.RegisterAttached(
+                name:="IsTransparent",
+                propertyType:=GetType(Boolean),
+                ownerType:=GetType(Canvas_IsTransparentInheritEnabled),
+                defaultMetadata:=New FrameworkPropertyMetadata(
+                    defaultValue:=False,
+                    flags:=FrameworkPropertyMetadataOptions.[Inherits]))
+
+        ' Declare a get accessor method.
+        Public Shared Function GetIsTransparent(element As Canvas) As Boolean
+            Return element.GetValue(IsTransparentProperty)
+        End Function
+
+        ' Declare a set accessor method.
+        Public Shared Sub SetIsTransparent(element As Canvas, value As Boolean)
+            element.SetValue(IsTransparentProperty, value)
+        End Sub
+
+        ' For convenience, declare a property wrapper with get/set accessors.
+        Public Property IsTransparent As Boolean
+            Get
+                Return GetValue(IsTransparentProperty)
+            End Get
+            Set(value As Boolean)
+                SetValue(IsTransparentProperty, value)
+            End Set
+        End Property
+    End Class
+    '</RegisterAttachedPropertyWithValueInheritance>
+
+    Public Class Canvas_IsTransparentInheritEnabled2
+        Inherits Canvas_IsTransparentInheritEnabled
+    End Class
+
+    Public Class Canvas_IsTransparentInheritEnabled3
+        Inherits Canvas_IsTransparentInheritEnabled
+    End Class
+
+    Public Class Canvas_IsTransparentInheritDisabled
+        Inherits Canvas
+
+        ' Register an attached dependency property with the specified
+        ' property name, property type, owner type, and property metadata
+        ' (default value is 'false' and property value inheritance is disabled).
+        Public Shared ReadOnly IsTransparentProperty As DependencyProperty =
+            DependencyProperty.RegisterAttached(
+                name:="IsTransparent",
+                propertyType:=GetType(Boolean),
+                ownerType:=GetType(Canvas_IsTransparentInheritDisabled),
+                defaultMetadata:=New FrameworkPropertyMetadata(defaultValue:=False))
+
+        ' Declare a get accessor method.
+        Public Shared Function GetIsTransparent(element As Canvas) As Boolean
+            Return element.GetValue(IsTransparentProperty)
+        End Function
+
+        ' Declare a set accessor method.
+        Public Shared Sub SetIsTransparent(element As Canvas, value As Boolean)
+            element.SetValue(IsTransparentProperty, value)
+        End Sub
+
+        ' For convenience, declare a property wrapper with get/set accessors.
+        Public Property IsTransparent As Boolean
+            Get
+                Return GetValue(IsTransparentProperty)
+            End Get
+            Set(value As Boolean)
+                SetValue(IsTransparentProperty, value)
+            End Set
+        End Property
+    End Class
+
+    Public Class Canvas_IsTransparentInheritDisabled2
+        Inherits Canvas_IsTransparentInheritDisabled
+    End Class
+
+    Public Class Canvas_IsTransparentInheritDisabled3
+        Inherits Canvas_IsTransparentInheritDisabled
+    End Class
+End Namespace