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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
using System.Reflection;
using System.Text;
using System.Windows.Markup;
namespace System.Windows
{
/// <summary>
/// ThemeDictionaryExtension allows application authors to customize
/// control styles based on the current system theme.
///
/// </summary>
[MarkupExtensionReturnType(typeof(Uri))]
public class ThemeDictionaryExtension : MarkupExtension
{
#region Constructors
/// <summary>
/// Constructor that takes no parameters
/// </summary>
public ThemeDictionaryExtension()
{
}
/// <summary>
/// Constructor that takes the name of the assembly that contains the themed ResourceDictionary.
/// </summary>
public ThemeDictionaryExtension(string assemblyName)
{
ArgumentNullException.ThrowIfNull(assemblyName);
_assemblyName = assemblyName;
}
#endregion
#region Public Properties
/// <summary>
/// The name of the assembly that contains the themed ResourceDictionary.
/// </summary>
public string AssemblyName
{
get { return _assemblyName; }
set { _assemblyName = value; }
}
#endregion
#region Public Methods
/// <summary>
/// Return an object that should be set on the targetObject's targetProperty
/// for this markup extension. For ThemeDictionaryExtension, this is the Uri
/// pointing to theme specific dictionary in the specified assembly by AssemblyName.
/// </summary>
/// <param name="serviceProvider">ServiceProvider that can be queried for services.</param>
/// <returns>
/// The object to set on this property.
/// </returns>
public override object ProvideValue(IServiceProvider serviceProvider)
{
if (string.IsNullOrEmpty(AssemblyName))
{
throw new InvalidOperationException(SR.ThemeDictionaryExtension_Name);
}
IProvideValueTarget provideValueTarget = serviceProvider.GetService(typeof(IProvideValueTarget)) as IProvideValueTarget;
if( provideValueTarget == null )
{
throw new InvalidOperationException(SR.Format(SR.MarkupExtensionNoContext, GetType().Name, "IProvideValueTarget" ));
}
object targetObject = provideValueTarget.TargetObject;
object targetProperty = provideValueTarget.TargetProperty;
ResourceDictionary dictionary = targetObject as ResourceDictionary;
PropertyInfo propertyInfo = targetProperty as PropertyInfo;
// Allow targetProperty to be null or ResourceDictionary.Source
if (dictionary == null || (targetProperty != null && propertyInfo != SourceProperty))
{
throw new InvalidOperationException(SR.ThemeDictionaryExtension_Source);
}
Register(dictionary, _assemblyName);
dictionary.IsSourcedFromThemeDictionary = true;
return GenerateUri(_assemblyName, SystemResources.ResourceDictionaries.ThemedResourceName, MS.Win32.UxThemeWrapper.ThemeName);
}
// Build the Uri for the assembly:
// /AssemblyName;Component/themes/<CurrentTheme>.<Color>.xaml
private static Uri GenerateUri(string assemblyName, string resourceName, string themeName)
{
StringBuilder uri = new StringBuilder(assemblyName.Length + 50);
uri.Append('/');
uri.Append(assemblyName);
// If assembly is PresentationFramework, append the Theme name
if (assemblyName.Equals(SystemResources.PresentationFrameworkName, StringComparison.OrdinalIgnoreCase))
{
uri.Append('.');
uri.Append(themeName);
}
uri.Append(";component/");
uri.Append(resourceName);
uri.Append(".xaml");
return new System.Uri(uri.ToString(), System.UriKind.RelativeOrAbsolute);
}
internal static Uri GenerateFallbackUri(ResourceDictionary dictionary, string resourceName)
{
for (int i = 0; i < _themeDictionaryInfos.Count; i++)
{
ThemeDictionaryInfo info = _themeDictionaryInfos[i];
if (!info.DictionaryReference.IsAlive)
{
// Remove from list
_themeDictionaryInfos.RemoveAt(i);
i--;
continue;
}
if ((ResourceDictionary)info.DictionaryReference.Target == dictionary)
{
string themeName = resourceName.Split('/')[1];
return GenerateUri(info.AssemblyName, resourceName, themeName);
}
}
return null;
}
#endregion
#region Data
private string _assemblyName;
#endregion
#region Static Data
// Keep track of all dictionaries that have ThemeDictionaryExtensions applied to them
// When the theme changes update the Source uri to point to the new theme info
// This is the ResourceDictionary.Source property info
private static PropertyInfo _sourceProperty;
private static PropertyInfo SourceProperty
{
get
{
if (_sourceProperty == null)
{
_sourceProperty = typeof(ResourceDictionary).GetProperty("Source");
}
return _sourceProperty;
}
}
private class ThemeDictionaryInfo
{
public WeakReference DictionaryReference;
public string AssemblyName;
}
// Store a list of dictionaries and assembly info's.
// When the theme changes, give the dictionaries a new Source Uri
[ThreadStatic]
private static List<ThemeDictionaryInfo> _themeDictionaryInfos;
private static void Register(ResourceDictionary dictionary, string assemblyName)
{
Debug.Assert(dictionary != null, "dictionary should not be null");
Debug.Assert(assemblyName != null, "assemblyName should not be null");
if (_themeDictionaryInfos == null)
{
_themeDictionaryInfos = new List<ThemeDictionaryInfo>();
}
ThemeDictionaryInfo info;
for (int i = 0; i < _themeDictionaryInfos.Count; i++)
{
info = _themeDictionaryInfos[i];
if (!info.DictionaryReference.IsAlive)
{
// Remove from list
_themeDictionaryInfos.RemoveAt(i);
i--;
continue;
}
if (info.DictionaryReference.Target == dictionary)
{
info.AssemblyName = assemblyName;
return;
}
}
// Not present, add to list
info = new ThemeDictionaryInfo();
info.DictionaryReference = new WeakReference(dictionary);
info.AssemblyName = assemblyName;
_themeDictionaryInfos.Add(info);
}
internal static void OnThemeChanged()
{
// Update all resource dictionaries
if (_themeDictionaryInfos != null)
{
for (int i = 0; i < _themeDictionaryInfos.Count; i++)
{
ThemeDictionaryInfo info = _themeDictionaryInfos[i];
if (!info.DictionaryReference.IsAlive)
{
// Remove from list
_themeDictionaryInfos.RemoveAt(i);
i--;
continue;
}
// Provide the new dictionary URI
ResourceDictionary dictionary = (ResourceDictionary)info.DictionaryReference.Target;
dictionary.Source = GenerateUri(info.AssemblyName, SystemResources.ResourceDictionaries.ThemedResourceName, MS.Win32.UxThemeWrapper.ThemeName);
}
}
}
#endregion
}
}
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