My Personal Commander Variant

// This file is part of the Lobster.MVVM library
// Copyright: Andreas Raczek
// This file is published under the The Code Project Open License (CPOL) 
// See the file "CPOL.html" for the full license governing this code.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;

namespace Lobster.MVVM
{
    public interface IWindowHandle 
    {
        void Show();

        void ShowModal();

        void Close();        
    }

    public class WindowHandle : IWindowHandle
    {
        public UIElementVM ViewModel { get; private set; }
        public Window Window { get; private set; }

        public WindowHandle(Window w, UIElementVM vm) {
            Window = w;
            ViewModel = vm;
        }

        public void Show()
        {
            Window.Show();
        }

        public void ShowModal()
        {
            Window.ShowDialog();
        }

        public void Close()
        {
            Window.Close();
        }
    }

    public interface IWindowServices
    {
        void Add(string name, Type t);
        bool Remove(string name);

        // IWindowHandle Create(string name, UIElementVM viewModel);
        IWindowHandle Create(string name, WindowVM viewModel, WindowVM parentViewModel);
        void CloseAllWindows();

        IWindowHandle GetWindowHandle(WindowVM viewModel);
    }

    public class WindowServices : IWindowServices
    {

        private Dictionary<string, Type> dialogTypes = new Dictionary<string,Type>();
        private List<WindowHandle> windows = new List<WindowHandle>();

        private int currentID = 0;
        private int getNewID() {
            return currentID++;
        }

        public void Add(string name, Type t)
        {
            dialogTypes.Add(name, t);
        }

        public bool Remove(string name)
        {
            return dialogTypes.Remove(name);
        }

        private IWindowHandle _Create(string name, UIElementVM viewModel, UIElementVM parentViewModel) 
        {
            if (!dialogTypes.ContainsKey(name)) throw new ArgumentException();

            Type t = dialogTypes[name];
            Window w = (Window)Activator.CreateInstance(t);

            if (null != parentViewModel)
            {
                var pwh = windows.Where((h) => h.ViewModel == parentViewModel).First();
                if (null != pwh)
                {
                    w.Owner = pwh.Window;
                }
            }

            w.DataContext = viewModel;
            var newWindow = new WindowHandle(w, viewModel);
            windows.Add(newWindow);
            return newWindow;
        }

        public IWindowHandle Create(string name, WindowVM viewModel, WindowVM parentViewModel) 
        {
            IWindowHandle dlgHandle = _Create(name, (UIElementVM) viewModel, parentViewModel);

            viewModel.RequestClose += (o, p) =>
            {
                dlgHandle.Close();
            };

            return dlgHandle;
        }

        public void CloseAllWindows()
        {
            foreach (var w in windows) w.Close();
        }

        public IWindowHandle GetWindowHandle(WindowVM viewModel)
        {
            foreach (var w in windows)
            {
                if (w.ViewModel == viewModel) return w;
            }
            return null;
        }
    }

}