标签：err fir and 框架 default lin obj dict wpf
实现主题更换功能主要是三个知识点：
Demo 代码地址：GITHUB
下面开门见山，直奔主题
在项目 (怎么建项目就不说了，百度上多得是) 下面新建一个文件夹 Themes，主题资源都放在这里面，这里我就简单实现了两个主题 Light /Dark，主题只包含背景颜色一个属性。
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:ModernUI.Example.Theme.Themes">
<Color x:Key="WindowBackgroundColor">#333</Color>
</ResourceDictionary><ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:ModernUI.Example.Theme.Themes">
<Color x:Key="WindowBackgroundColor">#ffffff</Color>
</ResourceDictionary>然后在程序的App.xaml中添加一个默认的主题
不同意义的资源最好分开到单独的文件里面，最后Merge到App.xaml里面，这样方便管理和搜索。
<Application x:Class="ModernUI.Example.Theme.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:ModernUI.Example.Theme"
StartupUri="MainWindow.xaml">
<Application.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="Themes/Theme.Light.xaml"/>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Application.Resources>
</Application>界面上我模仿 ModernUI ，使用ComboBox 控件来更换主题，所以这边需要实现一个视图模型用来被 ComboBox 绑定。
新建一个文件夹 Prensentation ，存放所有的数据模型类文件
NotifyPropertyChanged 类实现 INotifyPropertyChanged 接口，是所有视图模型的基类，主要用于实现数据绑定功能。
abstract class NotifyPropertyChanged : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged([CallerMemberName]string propertyName = "")
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}这里面用到了一个 [CallerMemberName] Attribute ，这个是.net 4.5里面的新特性，可以实现形参的自动填充，以后在属性中调用 OnPropertyChanged 方法就不用在输入形参了，这样更利于重构，不会因为更改属性名称后，忘记更改 OnPropertyChanged 的输入参数而导致出现BUG。具体可以参考 C# in depth (第五版) 16.2 节 的内容
Displayable 用来实现界面呈现的数据，ComboBox Item上显示的字符串就是 DisplayName 这个属性
class Displayable : NotifyPropertyChanged
{
private string _displayName { get; set; }
/// <summary>
/// name to display on ui
/// </summary>
public string DisplayName
{
get => _displayName;
set
{
if (_displayName != value)
{
_displayName = value;
OnPropertyChanged();
}
}
}
}Link 类继承自 Displayable ，主要用于保存界面上显示的主题名称(DisplayName)，以及主题资源的路径(Source)
class Link : Displayable
{
private Uri _source = null;
/// <summary>
/// resource uri
/// </summary>
public Uri Source
{
get => _source;
set
{
_source = value;
OnPropertyChanged();
}
}
}LinkCollection 继承自 ObservableCollection<Link>，被 ComboBox 的 ItemsSource 绑定，当集合内的元素发生变化时，ComboBox 的 Items 也会一起变化。
class LinkCollection : ObservableCollection<Link>
{
/// <summary>
/// Initializes a new instance of the <see cref="LinkCollection"/> class.
/// </summary>
public LinkCollection()
{
}
/// <summary>
/// Initializes a new instance of the <see cref="LinkCollection"/> class that contains specified links.
/// </summary>
/// <param name="links">The links that are copied to this collection.</param>
public LinkCollection(IEnumerable<Link> links)
{
if (links == null)
{
throw new ArgumentNullException("links");
}
foreach (var link in links)
{
Add(link);
}
}
}ThemeManager 类用于管理当前正在使用的主题资源，使用单例模式 (Singleton) 实现。
class ThemeManager : NotifyPropertyChanged
{
#region singletion
private static ThemeManager _current = null;
private static readonly object _lock = new object();
public static ThemeManager Current
{
get
{
if (_current == null)
{
lock (_lock)
{
if (_current == null)
{
_current = new ThemeManager();
}
}
}
return _current;
}
}
#endregion
/// <summary>
/// get current theme resource dictionary
/// </summary>
/// <returns></returns>
private ResourceDictionary GetThemeResourceDictionary()
{
return (from dictionary in Application.Current.Resources.MergedDictionaries
where dictionary.Contains("WindowBackgroundColor")
select dictionary).FirstOrDefault();
}
/// <summary>
/// get source uri of current theme resource
/// </summary>
/// <returns>resource uri</returns>
private Uri GetThemeSource()
{
var theme = GetThemeResourceDictionary();
if (theme == null)
return null;
return theme.Source;
}
/// <summary>
/// set the current theme source
/// </summary>
/// <param name="source"></param>
public void SetThemeSource(Uri source)
{
var oldTheme = GetThemeResourceDictionary();
var dictionaries = Application.Current.Resources.MergedDictionaries;
dictionaries.Add(new ResourceDictionary
{
Source = source
});
if (oldTheme != null)
{
dictionaries.Remove(oldTheme);
}
}
/// <summary>
/// current theme source
/// </summary>
public Uri ThemeSource
{
get => GetThemeSource();
set
{
if (value != null)
{
SetThemeSource(value);
OnPropertyChanged();
}
}
}
}SettingsViewModel 类用于绑定到 ComboBox 的 DataContext 属性，构造器中会初始化 Themes 属性，并将我们预先定义的主题资源添加进去。
ComboBox.SelectedItem -> SettingsViewModel.SelectedTheme
ComboBox.ItemsSource -> SettingsViewModel.Themes
class SettingsViewModel : NotifyPropertyChanged
{
public LinkCollection Themes { get; private set; }
private Link _selectedTheme = null;
public Link SelectedTheme
{
get => _selectedTheme;
set
{
if (value == null)
return;
if (_selectedTheme != value)
_selectedTheme = value;
ThemeManager.Current.ThemeSource = value.Source;
OnPropertyChanged();
}
}
public SettingsViewModel()
{
Themes = new LinkCollection()
{
new Link { DisplayName = "Light", Source = new Uri(@"Themes/Theme.Light.xaml" , UriKind.Relative) } ,
new Link { DisplayName = "Dark", Source = new Uri(@"Themes/Theme.Dark.xaml" , UriKind.Relative) }
};
SelectedTheme = Themes.FirstOrDefault(dcts => dcts.Source.Equals(ThemeManager.Current.ThemeSource));
}
}主窗口使用 Border 控件来控制背景颜色，Border 的 Background.Color 指向到动态资源 WindowBackgroundColor ，这个 WindowBackgroundColor 就是我们在主题资源中定义好的 Color 的 Key，因为需要动态更换主题，所以需要用DynamicResource 实现。
Border 背景动画比较简单，就是更改 SolidColorBrush 的 Color 属性。
ComboBox 控件绑定了三个属性 ：
<Window ...>
<Grid>
<Border x:Name="Border">
<Border.Background>
<SolidColorBrush x:Name="WindowBackground" Color="{DynamicResource WindowBackgroundColor}"/>
</Border.Background>
<Border.Resources>
<Storyboard x:Key="BorderBackcolorAnimation">
<ColorAnimation
Storyboard.TargetName="WindowBackground" Storyboard.TargetProperty="Color"
To="{DynamicResource WindowBackgroundColor}"
Duration="0:0:0.5" AutoReverse="False">
</ColorAnimation>
</Storyboard>
</Border.Resources>
<ComboBox x:Name="ThemeComboBox"
VerticalAlignment="Top" HorizontalAlignment="Left" Margin="30,10,0,0" Width="150"
DisplayMemberPath="DisplayName"
ItemsSource="{Binding Themes }"
SelectedItem="{Binding SelectedTheme , Mode=TwoWay}" >
</ComboBox>
</Border>
</Grid>
</Window>后台代码将 ComboBox.DataContext 引用到 SettingsViewModel ，实现数据绑定，同时监听 ThemeManager.Current.PropertyChanged 事件，触发背景动画
public partial class MainWindow : Window
{
private Storyboard _backcolorStopyboard = null;
public MainWindow()
{
InitializeComponent();
ThemeComboBox.DataContext = new Presentation.SettingsViewModel();
Presentation.ThemeManager.Current.PropertyChanged += AppearanceManager_PropertyChanged;
}
private void AppearanceManager_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
{
if (_backcolorStopyboard != null)
{
_backcolorStopyboard.Begin();
}
}
public override void OnApplyTemplate()
{
base.OnApplyTemplate();
if (Border != null)
{
_backcolorStopyboard = Border.Resources["BorderBackcolorAnimation"] as Storyboard;
}
}
}关键点：
另外写的比较啰嗦，主要是给自己回过头来复习看的。。。这年头WPF也没什么市场了，估计也没什么人看吧 o(╥﹏╥)o
标签：err fir and 框架 default lin obj dict wpf
原文地址：https://www.cnblogs.com/ArthurRen/p/9537645.html
