HuNan_DM/DM_Weight/App.xaml

<prism:PrismApplication x:Class="DM_Weight.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"
             d1p1:Ignorable="d"
             xmlns:materialDesign="http://materialdesigninxaml.net/winfx/xaml/themes"
             xmlns:local="clr-namespace:DM_Weight"
             xmlns:prism="http://prismlibrary.com/" Startup="PrismApplication_Startup">
    <Application.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <materialDesign:BundledTheme BaseTheme="Light" PrimaryColor="Indigo" SecondaryColor="Cyan" />
                <ResourceDictionary Source="pack://application:,,,/MaterialDesignThemes.Wpf;component/Themes/MaterialDesignTheme.Defaults.xaml" />

            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Application.Resources>
    </prism:PrismApplication>