Что такое маршалинг?csharp-121

[DllImport("user32.dll", CharSet = CharSet.Auto)]
public static extern int MessageBox(
    IntPtr hWnd,
    [MarshalAs(UnmanagedType.LPTStr)] string text,
    [MarshalAs(UnmanagedType.LPTStr)] string caption,
    uint type);

// Вызов неуправляемого кода с маршалингом строк
MessageBox(IntPtr.Zero, "Hello World", "Title", 0);

// Маршалинг COM объекта в .NET
[ComImport]
[Guid("000208D5-0000-0000-C000-000000000046")]
[InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
public interface IExcelApplication
{
    void Quit();
}

// Использование
Type excelType = Type.GetTypeFromProgID("Excel.Application");
dynamic excel = Activator.CreateInstance(excelType);
excel.Quit(); // Маршалинг вызова через RCW

public class MarshalByRefObjectExample : MarshalByRefObject
{
    public string GetDomainName() => AppDomain.CurrentDomain.FriendlyName;
}

// В другом домене
var domain = AppDomain.CreateDomain("NewDomain");
var obj = (MarshalByRefObjectExample)domain.CreateInstanceAndUnwrap(
    typeof(MarshalByRefObjectExample).Assembly.FullName,
    typeof(MarshalByRefObjectExample).FullName);
Console.WriteLine(obj.GetDomainName()); // "NewDomain"

[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public struct Person
{
    [MarshalAs(UnmanagedType.LPWStr)]
    public string Name;
    public int Age;
}

public class CustomMarshaller : ICustomMarshaler
{
    public static ICustomMarshaler GetInstance(string cookie) => new CustomMarshaller();

    public void CleanUpManagedData(object ManagedObj) { ... }
    public void CleanUpNativeData(IntPtr pNativeData) { ... }
    // ... другие методы интерфейса
}

[DllImport("kernel32.dll", CharSet = CharSet.Auto)]
public static extern bool GetDiskFreeSpaceEx(
    string directoryName,
    out ulong freeBytesAvailable,
    out ulong totalNumberOfBytes,
    out ulong totalNumberOfFreeBytes);

// Использование
ulong free, total, totalFree;
GetDiskFreeSpaceEx(@"C:\", out free, out total, out totalFree);