laatzen/Common/Ui/Common.UI.VFM/ViewModels/AppViewModel.cs

namespace Common.UI.VFM.ViewModels
{
    using Common.UI.VFM.Views;

    using System;
    using System.ComponentModel;
    using System.Configuration;
    using System.Runtime.CompilerServices;
    using System.Windows;
    using System.Windows.Input;

    public class AppViewModel : INotifyPropertyChanged
    {
        protected AppViewModel() => App.Exiting += this.Dispose;

        public event PropertyChangedEventHandler PropertyChanged;

        protected String PortName => ConfigurationManager.AppSettings[nameof(this.PortName)];

        protected String SqlConnectionString => ConfigurationManager.AppSettings[nameof(this.SqlConnectionString)];

        protected String LabelServer => ConfigurationManager.AppSettings[nameof(this.LabelServer)];

        public virtual void Dispose() => App.Exiting -= this.Dispose;

        protected void NotifyPropertyChanged([CallerMemberName] String property = "") 
            => this.PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(property));

        protected void Set(Action setExpression, [CallerMemberName] String property = "")
        {
            setExpression?.Invoke();

            this.NotifyPropertyChanged(property);
        }

        protected class Command : ICommand
        {
            private readonly Action executable;

            public Command(Action executable)
            {
                this.executable = executable;
            }

            public event EventHandler CanExecuteChanged
            {
                add => CommandManager.RequerySuggested += value;
                remove => CommandManager.RequerySuggested -= value;
            }

            public bool CanExecute(Object _)
            {
                return this.executable != null;
            }

            public void Execute(Object _)
            {
                this.executable?.Invoke();
            }
        }

        protected class Command<T> : ICommand
        {
            private readonly Action<T> executable;

            public Command(Action<T> executable)
            {
                this.executable = executable;
            }

            public event EventHandler CanExecuteChanged
            {
                add => CommandManager.RequerySuggested += value;
                remove => CommandManager.RequerySuggested -= value;
            }

            public bool CanExecute(Object _)
            {
                return this.executable != null;
            }

            public void Execute(Object parameter)
            {
                this.executable?.Invoke(parameter is T t ? t : default(T));
            }
        }
    }
}