ICommand secrets :) Can I creamte my own ICommand replacement ?

Hi, ok once again . The code is below. If I exchange the ICommand and my ICommandX, the program does not work - it is if I run it and put down a text upper into text box and push the button no message box is appeared. If I put back the name ICommand, everything is working ok.

Here is complette source code:
https://drive.google.com/file/d/1EITi5SLB1WqVnLL0cSWV4F4F2vLnNBVt/view?usp=sharing

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Input;


/*
#region Assembly System.ObjectModel, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
// C:\Program Files\dotnet\packs\Microsoft.NETCore.App.Ref\5.0.0\ref\net5.0\System.ObjectModel.dll
#endregion

#nullable enable
*/

using System.ComponentModel;
using System.Windows.Markup;
using System.ComponentModel.DataAnnotations;

namespace WpfApp
{


    [TypeConverter("System.Windows.Input.CommandConverter, PresentationFramework, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, Custom=null")]
    [ValueSerializer("System.Windows.Input.CommandValueSerializer, PresentationFramework, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, Custom=null")]
    public interface ICommandX
    {
        event EventHandler? CanExecuteChanged;
        bool CanExecute(object? parameter);
        void Execute(object? parameter);
    }



    public class VM
    {

        public String Name { get; set; }

        private ICommandX _SaveCommand;

        public ICommandX SaveCommand
        {
            get { return _SaveCommand;  }
        }


        public VM()
        {
            _SaveCommand = new RelayCommand(SaveCommand_Execute, SaveCommand_CanExecute);
        }



        public void SaveCommand_Execute() 
        {
            MessageBox.Show("Save called");
        }

        public bool SaveCommand_CanExecute()
        {

            if ( string.IsNullOrEmpty(Name))
            {
                return false;
            }
            else
            {
                return true;
            }

        }


    }

    public class RelayCommand : ICommandX
    {
        private Action methodToxecute;
        private Func<bool> canExecuteEvaluator;

        public event EventHandler CanExecuteChanged
        {
            add 
            { 
                CommandManager.RequerySuggested += value;
                //MessageBox.Show(value.ToString());

            }
            remove { CommandManager.RequerySuggested -= value; }
        }


        public RelayCommand(Action methodToExecute, Func<bool> canExecuteEvaluator)
        {
            this.methodToxecute = methodToExecute;
            this.canExecuteEvaluator = canExecuteEvaluator;
        }

        public RelayCommand(Action methodToExecute) : this(methodToExecute, null)
        {

        }

        public bool CanExecute(object parameter)
        {
            if ( this.canExecuteEvaluator == null)
            {
                return true;
            }
            else
            {
                bool result = this.canExecuteEvaluator.Invoke();
                return result;
            }
        }

        public void Execute(object parameter)
        {
            this.methodToxecute.Invoke();
        }

    }
}