Morrowind

<DataGridTextColumn Width="*" Header="Имя пользователя" Binding="{Binding User[0].username}"></DataGridTextColumn>

 <DataGridTextColumn Width="*" Header="ФИО" Binding="{Binding User[0].FullName}"></DataGridTextColumn>

<DataGrid x:Name="Dg_Login" Grid.Row="1" AutoGenerateColumns="False" ItemsSource="{Bunding CollectionDbObject}"> 
<DataGrid.Columns>
<DataGridTextColumn Width="*" Header="Имя пользователя" Binding="{Binding username}"></DataGridTextColumn>
<DataGridTextColumn Width="*" Header="ФИО" Binding="{Binding FullName}"></DataGridTextColumn>
<DataGridTextColumn Width="*" Header="Результат входа" Binding="{Binding State1}"></DataGridTextColumn>
 <DataGridTextColumn Width="*" Header="Дата" Binding="{Binding Date, StringFormat=dd.MM.yyyy HH:mm:ss}"></DataGridTextColumn>
</DataGrid.Columns>

int [] mass = new int[5];
int a = 15;
int b = 66;

public void AddInt(int number)
{
if (number > 0 & number <= 20)
{
    mass[0] = number;
}
else if (number > 20)
{
    mass[1] = number;
}

}

AddInt(a);
AddInt(b);

IHost host = Host.CreateDefaultBuilder(args)
    .ConfigureHostConfiguration(builder =>
    {
        builder.SetBasePath(System.IO.Directory.GetCurrentDirectory());
    
    })

    .ConfigureServices(services =>
    {
        services.AddHostedService<Worker>();
      var config = new ConfigurationBuilder()
              .SetBasePath(System.IO.Directory.GetCurrentDirectory())
              .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
              .AddEnvironmentVariables()
              .Build();
     
        services.AddSingleton<IRunner, Runner>()
        .AddLogging(loggingBuilder =>
        {
            // configure Logging with NLog
            loggingBuilder.ClearProviders();
            loggingBuilder.SetMinimumLevel(Microsoft.Extensions.Logging.LogLevel.Debug);
            loggingBuilder.AddNLog(config);
        });
        services.AddSingleton<IEmailService, EmailService>();
        services.AddSingleton<IClientSmtp, SmtpClientGoogleAsync>();
        services.AddSingleton<ICheckingSubEmailService, CheckingSubEmailService>();
    })
    .UseWindowsService()
    .Build();

if(bookPriceDb == null)
{
 throw new NullReferenceException ("не существует указанного id: {bookingId} ")
}

Magazine item = new Magazine();
item.Product  = "Hook";

class Magazine
{
    public string Product { get; init; }
}
Magazine item = new Magazine(){ Product = "Soda" };