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https://github.com/Stone-Red-Code/docs-desktop.git
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Content update - How to override dependency property metadata (user story 1878471) (#1205)
* Add article, snippets, toc, and redirects * Minor edit to dependency-property-metadata article * Update dotnet-desktop-guide/net/wpf/properties/how-to-override-metadata-for-a-dependency-property.md Co-authored-by: Andy (Steve) De George <[email protected]> Co-authored-by: Andy (Steve) De George <[email protected]>
This commit is contained in:
Tris Shores
co-authored by
Andy De George
Andy De George
parent
b82ed37802
commit
c065be138a
@@ -38,7 +38,7 @@ The <xref:System.Windows.PropertyMetadata> class stores most of the metadata use
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- Types that add themselves as an owner of a dependency property.
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If a type registers a dependency property without specifying metadata, the property system assigns a default `PropertyMetadata` object with default values for that type to the dependency property.
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If a type registers a dependency property without specifying metadata, the property system assigns a `PropertyMetadata` object with default values for that type to the dependency property.
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To retrieve metadata for a dependency property, call one of the <xref:System.Windows.DependencyProperty.GetMetadata%2A> overloads on the <xref:System.Windows.DependencyProperty> identifier. The metadata is returned as a `PropertyMetadata` object.
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+39
@@ -0,0 +1,39 @@
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---
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title: "How to override metadata for a dependency property"
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description: "Learn how to override a dependency property in Windows Presentation Foundation (WPF) by calling the OverrideMetadata method."
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ms.date: "11/04/2021"
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dev_langs:
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- "csharp"
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- "vb"
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helpviewer_keywords:
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- "metadata [WPF], overriding for dependency properties"
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- "dependency properties [WPF], overriding metadata for"
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- "overriding metadata for dependency properties [WPF]"
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---
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<!-- The acrolinx score was 92 on 11/04/2021-->
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# How to override metadata for a dependency property (WPF .NET)
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When you derive from a class that defines a dependency property, you inherit the dependency property and its metadata. This article describes how you can override the metadata of an inherited dependency property by calling the <xref:System.Windows.DependencyProperty.OverrideMetadata%2A> method. Overriding the metadata lets you modify characteristics of the inherited dependency property to match subclass-specific requirements.
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## Background
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A class that defines a dependency property can specify its characteristics in <xref:System.Windows.PropertyMetadata> or one of its derived types, such as <xref:System.Windows.FrameworkPropertyMetadata>. Examples of those characteristics are the default value and callback references that trigger on property change and/or coercion value change. Many classes that define dependency properties, specify property metadata during dependency property registration. When metadata isn't specified during registration, the WPF property system assigns a `PropertyMetadata` object with default values. Derived classes that inherit dependency properties through class inheritance have the option to override the original metadata of any dependency property. In this way, derived classes can selectively modify dependency property characteristics to meet class requirements. When calling <xref:System.Windows.DependencyProperty.OverrideMetadata(System.Type,System.Windows.PropertyMetadata)>, a derived class specifies its own type as the first parameter, and a metadata instance as the second parameter.
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A derived class that overrides metadata on a dependency property must do so before the property is placed in use by the property system. A dependency property is placed in use when any instance of the class that registers the property is instantiated. To help meet this requirement, the derived class should call <xref:System.Windows.DependencyProperty.OverrideMetadata%2A> within its static constructor. Overriding the metadata of a dependency property after its owner type is instantiated won't raise exceptions, but will result in inconsistent behaviors in the property system. Also, a derived type can't override the metadata of a dependency property more than once, and attempts to do so will raise an exception.
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## Example
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In the following example, the derived class `TropicalAquarium` overrides the metadata of a dependency property inherited from the base class `Aquarium`. The metadata type is <xref:System.Windows.FrameworkPropertyMetadata>, which supports UI-related WPF framework characteristics such as <xref:System.Windows.FrameworkPropertyMetadataOptions.AffectsRender>. The derived class doesn't override the inherited `AffectsRender` flag, but it does update the default value of `AquariumGraphic` on derived class instances.
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:::code language="csharp" source="./snippets/how-to-override-metadata-for-a-dependency-property/csharp/MainWindow.xaml.cs" id="BaseDependencyProperty":::
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:::code language="vb" source="./snippets/how-to-override-metadata-for-a-dependency-property/vb/MainWindow.xaml.vb" id="BaseDependencyProperty":::
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:::code language="csharp" source="./snippets/how-to-override-metadata-for-a-dependency-property/csharp/MainWindow.xaml.cs" id="InheritedDependencyProperty":::
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:::code language="vb" source="./snippets/how-to-override-metadata-for-a-dependency-property/vb/MainWindow.xaml.vb" id="InheritedDependencyProperty":::
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## See also
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- <xref:System.Windows.DependencyProperty>
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- [Dependency property metadata](dependency-property-metadata.md)
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- [Dependency properties overview](dependency-properties-overview.md)
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- [Custom dependency properties](custom-dependency-properties.md)
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+17
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using System;
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using System.Collections.Generic;
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using System.Configuration;
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using System.Data;
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using System.Linq;
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using System.Threading.Tasks;
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using System.Windows;
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namespace CodeSampleCsharp
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{
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/// <summary>
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/// Interaction logic for App.xaml
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/// </summary>
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public partial class App : Application
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{
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}
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}
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+10
@@ -0,0 +1,10 @@
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using System.Windows;
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[assembly: ThemeInfo(
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ResourceDictionaryLocation.None, //where theme specific resource dictionaries are located
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//(used if a resource is not found in the page,
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// or application resource dictionaries)
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ResourceDictionaryLocation.SourceAssembly //where the generic resource dictionary is located
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//(used if a resource is not found in the page,
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// app, or any theme specific resource dictionaries)
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)]
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+24
@@ -0,0 +1,24 @@
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<Project Sdk="Microsoft.NET.Sdk">
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<PropertyGroup>
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<OutputType>WinExe</OutputType>
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<TargetFramework>net5.0-windows</TargetFramework>
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<UseWPF>true</UseWPF>
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</PropertyGroup>
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<ItemGroup>
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<Compile Update="Properties\Resources.Designer.cs">
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<DesignTime>True</DesignTime>
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<AutoGen>True</AutoGen>
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<DependentUpon>Resources.resx</DependentUpon>
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</Compile>
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</ItemGroup>
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<ItemGroup>
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<EmbeddedResource Update="Properties\Resources.resx">
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<Generator>ResXFileCodeGenerator</Generator>
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<LastGenOutput>Resources.Designer.cs</LastGenOutput>
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</EmbeddedResource>
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</ItemGroup>
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</Project>
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+8
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<Window x:Class="CodeSampleCsharp.MainWindow"
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xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
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xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
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Title="How to override dependency property metadata" Height="200" Width="800" Loaded="ValidateSnippet">
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<Grid>
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<Label x:Name="lblMessage" HorizontalAlignment="Stretch" Margin="10" VerticalAlignment="Stretch"/>
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</Grid>
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</Window>
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+75
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using System;
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using System.Windows;
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namespace CodeSampleCsharp
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{
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/// <summary>
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/// Interaction logic for MainWindow.xaml.
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/// </summary>
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public partial class MainWindow : Window
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{
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public MainWindow() => InitializeComponent();
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public void ValidateSnippet(object sender, RoutedEventArgs e)
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{
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TropicalAquarium tropicalAquarium = new();
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Aquarium aquarium = new();
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FrameworkPropertyMetadata aquariumPropertyMetadata = (FrameworkPropertyMetadata)Aquarium.AquariumGraphicProperty.GetMetadata(aquarium);
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FrameworkPropertyMetadata tropicalAquariumPropertyMetadata = (FrameworkPropertyMetadata)Aquarium.AquariumGraphicProperty.GetMetadata(tropicalAquarium);
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lblMessage.Content = $"Tropical aquarium graphic URL: " + $"{tropicalAquarium.AquariumGraphic.OriginalString}" + Environment.NewLine;
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lblMessage.Content += $"Aquarium graphic URL: " + $"{aquarium.AquariumGraphic.OriginalString}" + Environment.NewLine;
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lblMessage.Content += $"Queried owner-type AquariumGraphic default value: " + $"{aquariumPropertyMetadata.DefaultValue}" + Environment.NewLine;
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lblMessage.Content += $"Queried owner-type AquariumGraphic affects render: " + $"{aquariumPropertyMetadata.AffectsRender}" + Environment.NewLine;
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lblMessage.Content += $"Queried derived-type TropicalAquarium default value: " + $"{tropicalAquariumPropertyMetadata.DefaultValue}" + Environment.NewLine;
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lblMessage.Content += $"Queried derived-type TropicalAquarium affects render: " + $"{tropicalAquariumPropertyMetadata.AffectsRender}" + Environment.NewLine;
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}
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}
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//<BaseDependencyProperty>
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public class Aquarium : DependencyObject
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{
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// Register a dependency property with the specified property name,
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// property type, owner type, and property metadata.
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public static readonly DependencyProperty AquariumGraphicProperty =
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DependencyProperty.Register(
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name: "AquariumGraphic",
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propertyType: typeof(Uri),
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ownerType: typeof(Aquarium),
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typeMetadata: new FrameworkPropertyMetadata(
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defaultValue: new Uri("http://www.contoso.com/aquarium-graphic.jpg"),
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flags: FrameworkPropertyMetadataOptions.AffectsRender)
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);
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// Declare a read-write CLR wrapper with get/set accessors.
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public Uri AquariumGraphic
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{
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get => (Uri)GetValue(AquariumGraphicProperty);
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set => SetValue(AquariumGraphicProperty, value);
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}
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}
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//</BaseDependencyProperty>
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//<InheritedDependencyProperty>
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public class TropicalAquarium : Aquarium
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{
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// Static constructor.
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static TropicalAquarium()
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{
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// Create a new metadata instance with a modified default value.
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FrameworkPropertyMetadata newPropertyMetadata = new(
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defaultValue: new Uri("http://www.contoso.com/tropical-aquarium-graphic.jpg"));
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// Call OverrideMetadata on the dependency property identifier.
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// Pass in the type for which the new metadata will be applied
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// and the new metadata instance.
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AquariumGraphicProperty.OverrideMetadata(
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forType: typeof(TropicalAquarium),
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typeMetadata: newPropertyMetadata);
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}
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}
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//</InheritedDependencyProperty>
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}
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+63
@@ -0,0 +1,63 @@
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//------------------------------------------------------------------------------
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||||
// <auto-generated>
|
||||
// This code was generated by a tool.
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||||
// Runtime Version:4.0.30319.42000
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||||
//
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// Changes to this file may cause incorrect behavior and will be lost if
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// the code is regenerated.
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// </auto-generated>
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//------------------------------------------------------------------------------
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namespace CodeSampleCsharp.Properties {
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using System;
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||||
/// <summary>
|
||||
/// A strongly-typed resource class, for looking up localized strings, etc.
|
||||
/// </summary>
|
||||
// This class was auto-generated by the StronglyTypedResourceBuilder
|
||||
// class via a tool like ResGen or Visual Studio.
|
||||
// To add or remove a member, edit your .ResX file then rerun ResGen
|
||||
// with the /str option, or rebuild your VS project.
|
||||
[global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Resources.Tools.StronglyTypedResourceBuilder", "16.0.0.0")]
|
||||
[global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
|
||||
[global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]
|
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internal class Resources {
|
||||
|
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private static global::System.Resources.ResourceManager resourceMan;
|
||||
|
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private static global::System.Globalization.CultureInfo resourceCulture;
|
||||
|
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[global::System.Diagnostics.CodeAnalysis.SuppressMessageAttribute("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
|
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internal Resources() {
|
||||
}
|
||||
|
||||
/// <summary>
|
||||
/// Returns the cached ResourceManager instance used by this class.
|
||||
/// </summary>
|
||||
[global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)]
|
||||
internal static global::System.Resources.ResourceManager ResourceManager {
|
||||
get {
|
||||
if (object.ReferenceEquals(resourceMan, null)) {
|
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global::System.Resources.ResourceManager temp = new global::System.Resources.ResourceManager("CodeSampleCsharp.Properties.Resources", typeof(Resources).Assembly);
|
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resourceMan = temp;
|
||||
}
|
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return resourceMan;
|
||||
}
|
||||
}
|
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|
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/// <summary>
|
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/// Overrides the current thread's CurrentUICulture property for all
|
||||
/// resource lookups using this strongly typed resource class.
|
||||
/// </summary>
|
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[global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)]
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internal static global::System.Globalization.CultureInfo Culture {
|
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get {
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return resourceCulture;
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||||
}
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set {
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resourceCulture = value;
|
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}
|
||||
}
|
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}
|
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}
|
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+120
@@ -0,0 +1,120 @@
|
||||
<?xml version="1.0" encoding="utf-8"?>
|
||||
<root>
|
||||
<!--
|
||||
Microsoft ResX Schema
|
||||
|
||||
Version 2.0
|
||||
|
||||
The primary goals of this format is to allow a simple XML format
|
||||
that is mostly human readable. The generation and parsing of the
|
||||
various data types are done through the TypeConverter classes
|
||||
associated with the data types.
|
||||
|
||||
Example:
|
||||
|
||||
... ado.net/XML headers & schema ...
|
||||
<resheader name="resmimetype">text/microsoft-resx</resheader>
|
||||
<resheader name="version">2.0</resheader>
|
||||
<resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
|
||||
<resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
|
||||
<data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
|
||||
<data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
|
||||
<data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
|
||||
<value>[base64 mime encoded serialized .NET Framework object]</value>
|
||||
</data>
|
||||
<data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
|
||||
<value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
|
||||
<comment>This is a comment</comment>
|
||||
</data>
|
||||
|
||||
There are any number of "resheader" rows that contain simple
|
||||
name/value pairs.
|
||||
|
||||
Each data row contains a name, and value. The row also contains a
|
||||
type or mimetype. Type corresponds to a .NET class that support
|
||||
text/value conversion through the TypeConverter architecture.
|
||||
Classes that don't support this are serialized and stored with the
|
||||
mimetype set.
|
||||
|
||||
The mimetype is used for serialized objects, and tells the
|
||||
ResXResourceReader how to depersist the object. This is currently not
|
||||
extensible. For a given mimetype the value must be set accordingly:
|
||||
|
||||
Note - application/x-microsoft.net.object.binary.base64 is the format
|
||||
that the ResXResourceWriter will generate, however the reader can
|
||||
read any of the formats listed below.
|
||||
|
||||
mimetype: application/x-microsoft.net.object.binary.base64
|
||||
value : The object must be serialized with
|
||||
: System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
|
||||
: and then encoded with base64 encoding.
|
||||
|
||||
mimetype: application/x-microsoft.net.object.soap.base64
|
||||
value : The object must be serialized with
|
||||
: System.Runtime.Serialization.Formatters.Soap.SoapFormatter
|
||||
: and then encoded with base64 encoding.
|
||||
|
||||
mimetype: application/x-microsoft.net.object.bytearray.base64
|
||||
value : The object must be serialized into a byte array
|
||||
: using a System.ComponentModel.TypeConverter
|
||||
: and then encoded with base64 encoding.
|
||||
-->
|
||||
<xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
|
||||
<xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
|
||||
<xsd:element name="root" msdata:IsDataSet="true">
|
||||
<xsd:complexType>
|
||||
<xsd:choice maxOccurs="unbounded">
|
||||
<xsd:element name="metadata">
|
||||
<xsd:complexType>
|
||||
<xsd:sequence>
|
||||
<xsd:element name="value" type="xsd:string" minOccurs="0" />
|
||||
</xsd:sequence>
|
||||
<xsd:attribute name="name" use="required" type="xsd:string" />
|
||||
<xsd:attribute name="type" type="xsd:string" />
|
||||
<xsd:attribute name="mimetype" type="xsd:string" />
|
||||
<xsd:attribute ref="xml:space" />
|
||||
</xsd:complexType>
|
||||
</xsd:element>
|
||||
<xsd:element name="assembly">
|
||||
<xsd:complexType>
|
||||
<xsd:attribute name="alias" type="xsd:string" />
|
||||
<xsd:attribute name="name" type="xsd:string" />
|
||||
</xsd:complexType>
|
||||
</xsd:element>
|
||||
<xsd:element name="data">
|
||||
<xsd:complexType>
|
||||
<xsd:sequence>
|
||||
<xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
|
||||
<xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
|
||||
</xsd:sequence>
|
||||
<xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
|
||||
<xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
|
||||
<xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
|
||||
<xsd:attribute ref="xml:space" />
|
||||
</xsd:complexType>
|
||||
</xsd:element>
|
||||
<xsd:element name="resheader">
|
||||
<xsd:complexType>
|
||||
<xsd:sequence>
|
||||
<xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
|
||||
</xsd:sequence>
|
||||
<xsd:attribute name="name" type="xsd:string" use="required" />
|
||||
</xsd:complexType>
|
||||
</xsd:element>
|
||||
</xsd:choice>
|
||||
</xsd:complexType>
|
||||
</xsd:element>
|
||||
</xsd:schema>
|
||||
<resheader name="resmimetype">
|
||||
<value>text/microsoft-resx</value>
|
||||
</resheader>
|
||||
<resheader name="version">
|
||||
<value>2.0</value>
|
||||
</resheader>
|
||||
<resheader name="reader">
|
||||
<value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
|
||||
</resheader>
|
||||
<resheader name="writer">
|
||||
<value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
|
||||
</resheader>
|
||||
</root>
|
||||
+9
@@ -0,0 +1,9 @@
|
||||
<Application x:Class="CodeSampleCsharp.App"
|
||||
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
|
||||
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
|
||||
xmlns:local="clr-namespace:CodeSampleCsharp"
|
||||
StartupUri="MainWindow.xaml">
|
||||
<Application.Resources>
|
||||
|
||||
</Application.Resources>
|
||||
</Application>
|
||||
+9
@@ -0,0 +1,9 @@
|
||||
<Application x:Class="Application"
|
||||
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
|
||||
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
|
||||
xmlns:local="clr-namespace:CodeSampleVb"
|
||||
StartupUri="MainWindow.xaml">
|
||||
<Application.Resources>
|
||||
|
||||
</Application.Resources>
|
||||
</Application>
|
||||
+6
@@ -0,0 +1,6 @@
|
||||
Class Application
|
||||
|
||||
' Application-level events, such as Startup, Exit, and DispatcherUnhandledException
|
||||
' can be handled in this file.
|
||||
|
||||
End Class
|
||||
+11
@@ -0,0 +1,11 @@
|
||||
Imports System.Windows
|
||||
|
||||
'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)>
|
||||
+22
@@ -0,0 +1,22 @@
|
||||
<Project Sdk="Microsoft.NET.Sdk">
|
||||
|
||||
<PropertyGroup>
|
||||
<OutputType>WinExe</OutputType>
|
||||
<TargetFramework>net5.0-windows</TargetFramework>
|
||||
<RootNamespace>CodeSampleVb</RootNamespace>
|
||||
<UseWPF>true</UseWPF>
|
||||
</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>
|
||||
+8
@@ -0,0 +1,8 @@
|
||||
<Window x:Class="CodeSampleVb.MainWindow"
|
||||
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
|
||||
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
|
||||
Title="How to override dependency property metadata" Height="200" Width="800" Loaded="ValidateSnippet">
|
||||
<Grid>
|
||||
<Label x:Name="lblMessage" HorizontalAlignment="Stretch" Margin="10" VerticalAlignment="Stretch"/>
|
||||
</Grid>
|
||||
</Window>
|
||||
+81
@@ -0,0 +1,81 @@
|
||||
Namespace CodeSampleVb
|
||||
|
||||
' <summary>
|
||||
' Interaction logic for MainWindow.xaml.
|
||||
' </summary>
|
||||
Partial Public Class MainWindow
|
||||
Inherits Window
|
||||
|
||||
Public Sub New()
|
||||
InitializeComponent()
|
||||
End Sub
|
||||
|
||||
Public Sub ValidateSnippet(sender As Object, e As RoutedEventArgs)
|
||||
Dim tropicalAquarium As New TropicalAquarium()
|
||||
Dim aquarium As New Aquarium()
|
||||
|
||||
Dim aquariumPropertyMetadata As FrameworkPropertyMetadata = CType(Aquarium.AquariumGraphicProperty.GetMetadata(aquarium), FrameworkPropertyMetadata)
|
||||
Dim tropicalAquariumPropertyMetadata As FrameworkPropertyMetadata = CType(Aquarium.AquariumGraphicProperty.GetMetadata(tropicalAquarium), FrameworkPropertyMetadata)
|
||||
|
||||
lblMessage.Content = $"Tropical aquarium graphic URL: {tropicalAquarium.AquariumGraphic.OriginalString}" & Environment.NewLine
|
||||
lblMessage.Content += $"Aquarium graphic URL: {aquarium.AquariumGraphic.OriginalString}" & Environment.NewLine
|
||||
|
||||
lblMessage.Content += $"Queried owner-type AquariumGraphic default value: {aquariumPropertyMetadata.DefaultValue}" & Environment.NewLine
|
||||
lblMessage.Content += $"Queried owner-type AquariumGraphic affects render: {aquariumPropertyMetadata.AffectsRender}" & Environment.NewLine
|
||||
|
||||
lblMessage.Content += $"Queried derived-type TropicalAquarium default value: {tropicalAquariumPropertyMetadata.DefaultValue}" & Environment.NewLine
|
||||
lblMessage.Content += $"Queried derived-type TropicalAquarium affects render: {tropicalAquariumPropertyMetadata.AffectsRender}" & Environment.NewLine
|
||||
End Sub
|
||||
|
||||
End Class
|
||||
|
||||
'<BaseDependencyProperty>
|
||||
Public Class Aquarium
|
||||
Inherits DependencyObject
|
||||
|
||||
' Register a dependency property with the specified property name,
|
||||
' property type, owner type, and property metadata.
|
||||
Public Shared ReadOnly AquariumGraphicProperty As DependencyProperty =
|
||||
DependencyProperty.Register(
|
||||
name:="AquariumGraphic",
|
||||
propertyType:=GetType(Uri),
|
||||
ownerType:=GetType(Aquarium),
|
||||
typeMetadata:=New FrameworkPropertyMetadata(
|
||||
defaultValue:=New Uri("http://www.contoso.com/aquarium-graphic.jpg"),
|
||||
flags:=FrameworkPropertyMetadataOptions.AffectsRender))
|
||||
|
||||
' Declare a read-write CLR wrapper with get/set accessors.
|
||||
Public Property AquariumGraphic As Uri
|
||||
Get
|
||||
Return CType(GetValue(AquariumGraphicProperty), Uri)
|
||||
End Get
|
||||
Set
|
||||
SetValue(AquariumGraphicProperty, Value)
|
||||
End Set
|
||||
End Property
|
||||
|
||||
End Class
|
||||
'</BaseDependencyProperty>
|
||||
|
||||
'<InheritedDependencyProperty>
|
||||
Public Class TropicalAquarium
|
||||
Inherits Aquarium
|
||||
|
||||
' Static constructor.
|
||||
Shared Sub New()
|
||||
' Create a new metadata instance with a modified default value.
|
||||
Dim newPropertyMetadata As New FrameworkPropertyMetadata(
|
||||
defaultValue:=New Uri("http://www.contoso.com/tropical-aquarium-graphic.jpg"))
|
||||
|
||||
' Call OverrideMetadata on the dependency property identifier.
|
||||
' Pass in the type for which the new metadata will be applied
|
||||
' and the new metadata instance.
|
||||
AquariumGraphicProperty.OverrideMetadata(
|
||||
forType:=GetType(TropicalAquarium),
|
||||
typeMetadata:=newPropertyMetadata)
|
||||
End Sub
|
||||
|
||||
End Class
|
||||
'</InheritedDependencyProperty>
|
||||
|
||||
End Namespace
|
||||
@@ -98,6 +98,8 @@ items:
|
||||
href: properties/how-to-implement-a-dependency-property.md
|
||||
- name: Register an attached property
|
||||
href: properties/how-to-register-an-attached-property.md
|
||||
- name: Override dependency property metadata
|
||||
href: properties/how-to-override-metadata-for-a-dependency-property.md
|
||||
- name: Resources
|
||||
items:
|
||||
- name: Overview
|
||||
|
||||
Reference in New Issue
Block a user