EmployeeTracker/InvestTracker/VM/EmployeeBrowseVM.cs

using InvestTracker.Entities;
using Microsoft.EntityFrameworkCore;
using Prism.Commands;
using Prism.Mvvm;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;

namespace InvestTracker.VM
{
    public class EmployeeBrowseVM : BindableBase
    {
        public DelegateCommand UndoCommand { get; set; }
        public DelegateCommand SaveCommand { get; set; }
        public DelegateCommand NewCommand { get; set; }
        public DelegateCommand EditCommand { get; set; }
        public DelegateCommand DeleteCommand { get; set; }
        public DelegateCommand FindCommand { get; set; }
        private InvestContext _dbContext;
        private bool isDirty = false;

        /// <summary>
        /// Список всех сотрудников
        /// </summary>
        public ObservableCollection<Employee> Employees { get; set; }

        /// <summary>
        /// Список всех должностей для выбора в колонках
        /// </summary>
        public ObservableCollection<Title> AllTitles { get; set; }

        public EmployeeBrowseVM()
        {
            UndoCommand = new DelegateCommand(Undo_Executed, WhenDirty);
            SaveCommand = new DelegateCommand(Save_Executed, WhenDirty);
            NewCommand = new DelegateCommand(New_Executed, WhenClean);
            EditCommand = new DelegateCommand(Edit_Executed, WhenClean);
            DeleteCommand = new DelegateCommand(Delete_Executed, WhenClean);
            FindCommand = new DelegateCommand(Find_Executed, WhenClean);

            _dbContext = new InvestContext();
            Employees = new ObservableCollection<Employee>(_dbContext.Employees.ToList());
            AllTitles = new ObservableCollection<Title>(_dbContext.Titles.ToList());
        }

        private void Undo_Executed()
        {
            MessageBox.Show("Undoing");
            isDirty = true;
        }

        private void Save_Executed()
        {
            MessageBox.Show("Saving");
            isDirty = false;
        }

        private void New_Executed()
        {
            MessageBox.Show("Adding...");
            isDirty = true;
        }

        private void Edit_Executed()
        {
            MessageBox.Show("Editing...");
            isDirty = true;
        }

        private void Delete_Executed()
        {
            MessageBox.Show("Deleting...");
            isDirty = true;
        }

        private void Find_Executed()
        {
            MessageBox.Show("Searching...");
        }
        
        /// <summary>
        /// CanExecute когда isDirty = false
        /// </summary>
        private bool WhenClean()
        {
            if (isDirty == false)
            {
                return true;
            } else
            {
                return false;
            }
        }

        /// <summary>
        /// CanExecute когда isDirty = true
        /// </summary>
        private bool WhenDirty()
        {
            if (isDirty == true)
            {
                return true;
            }
            else
            {
                return false;
            }
        }
    }
}