程序启动前设置主题样式

修改App.xaml文件，如下：

<Application
    x:Class="InvestmentDiary.Net.App"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:d1p1="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:materialDesign="http://materialdesigninxaml.net/winfx/xaml/themes"
    d1p1:Ignorable="d"
    StartupUri="View/Window/MainWindow.xaml">
    <Application.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <materialDesign:BundledTheme
                    BaseTheme="Dark"
                    PrimaryColor="Red"
                    SecondaryColor="Green" />
                <!--<materialDesign:BundledTheme
                    BaseTheme="Light"
                    PrimaryColor="Blue"
                    SecondaryColor="Blue" />-->
                <ResourceDictionary Source="pack://application:,,,/MaterialDesignThemes.Wpf;component/Themes/MaterialDesignTheme.Defaults.xaml" />
                <ResourceDictionary Source="Style/StringResource.xaml" />
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Application.Resources>
</Application>