EEMS/EEMSMain/Views/MainWindow.xaml

<Window x:Class="EEMSMain.Views.MainWindow"
        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:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:EEMSMain.Views"
        mc:Ignorable="d"
        xmlns:prism="http://prismlibrary.com/"
        prism:ViewModelLocator.AutoWireViewModel="True"
        Title="MainWindow" Height="450" Width="800">
    <DockPanel>
        <StackPanel Width="200">
            <Button Content="打开ViewA" Command="{Binding OpenCommand}"/>
            <Button Content="打开ViewB"/>
        </StackPanel>

        <ContentControl prism:RegionManager.RegionName="MainRegion"/>
    </DockPanel>
</Window>