Shaker/Avalonia/ShakerApp/Convert/Type2ViewConverter.cs

using Avalonia.Controls;
using Avalonia.Data.Converters;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ShakerApp.Convert
{
    public class Type2ViewConverter : IValueConverter
    {
        ConcurrentDictionary<RuntimeTypeHandle, Control> Views = new ConcurrentDictionary<RuntimeTypeHandle,Control>();
        public object? Convert(object? value, Type targetType, object? parameter, CultureInfo culture)
        {
            if (value is Type type)
            {
                if (parameter != null) return (Control)Activator.CreateInstance(type)!;
                else
                {
                    if (Views.TryGetValue(type.TypeHandle, out var view))
                    {
                        if(view.Parent is ContentControl window)
                        {
                            window.Content = null;
                        }
                        return view;
                    }
                    else
                    {
                        view = (Control)Activator.CreateInstance(type)!;
                        Views[type.TypeHandle] = view;
                        return view;
                    }
                }
            }
            if(value is IList<Type> types)
            {
                if (parameter != null) return types.Where(x => x != null).Select(x => Activator.CreateInstance(x));
                else
                {
                   return types.Where(x => x != null)
                        .Select(x =>
                        {
                            if (Views.TryGetValue(x.TypeHandle, out var view)) return view;
                            else
                            {
                                view = (Control)Activator.CreateInstance(x)!;
                                Views[x.TypeHandle] = view;
                                return view;
                            }
                        });
                }
            }
            return null;
        }

        public object? ConvertBack(object? value, Type targetType, object? parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }
}