//在App.xaml中添加以下代码：

<Application.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="pack://application:,,,/HandyControl;component/Themes/SkinDefault.xaml"/>
            <ResourceDictionary Source="pack://application:,,,/HandyControl;component/Themes/Theme.xaml"/>
        </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>
</Application.Resources>

//添加命名空间：
xmlns:hc="https://handyorg.github.io/handycontrol"
xmlns:controls="clr-namespace:HandyControl.Controls;assembly=HandyControl"

//添加Visifire.Charts命名空间：
xmlns:vc="clr-namespace:Visifire.Charts;assembly=WPFVisifire.Charts"