C# 如何在MVVM中创建聚合视图模型？

如何在MVVM中创建聚合视图模型？基本上我想将多个视图模型添加到一起。这是我试过的

using System;
using System.Windows.Input;
using Microsoft.VisualStudio.Shell.Interop;

namespace NavigationAssistant
{
    internal class NavigationAssistantViewModel
    {
        private IVsUIShell uiShell;

        private IServiceProvider _serviceProvider { get; }

        public NavigationAssistantViewModel(IVsUIShell uiShell, IServiceProvider serviceProvider)
        {
            this.uiShell = uiShell;
            this._serviceProvider = serviceProvider;
        }

        private ICommand changeThemeCommand;

        public ICommand ChangeThemeCommand
        {
            get
            {
                return this.changeThemeCommand ?? (this.changeThemeCommand = new VSCommand(this._serviceProvider, this.uiShell));
            }
        }
   }
}

---

没有更多的信息，我过去所做的只是两件事之一

将每个MVVM类重构为独立的MVVM类

创建一个包含相关类的MVVM类

internal class WrapperViewModel
{
    private IVsUIShell uiShell;
    private IServiceProvider _serviceProvider { get; }

    public WrapperViewModel(IVsUIShell uiShell, IServiceProvider serviceProvider)
    {
    }        

    //multiple classes
    public NavigationAssistantViewModel NavigationAssistantViewModel { get;set;}
    public MvvmClass2 MvvmClass2 { get;set;}
}

//multiple classes      
private class NavigationAssistantViewModel {

}

private class MvvmClass2 {

}

这有用吗？如果没有，你能澄清你的问题吗