[StructLayout(LayoutKind.Sequential)]
 public struct COPYDATASTRUCT
 {
  public IntPtr dwData;
  public int cbData;
  [MarshalAs(UnmanagedType.LPStr)]
  public string lpData;
 }
 [Serializable]
 public class Person
 {
  private string name;
  private int age;
  private List<Person> children;
  public Person(string name, int age)
  {
   this.name = name;
   this.age = age;
   this.children = new List<Person>();
  }
  public string Name
  {
   get { return this.name; }
   set { this.name = value; }
  }
  public int Age
  {
   get { return this.age; }
   set { this.age = value; }
  }
  public List<Person> Children
  {
   get { return this.children; }
  }
  public void AddChildren()
  {
   this.children.Add(new Person("liuxm", 9));
   this.children.Add(new Person("liuhm", 7));
  }
  public override string ToString()
  {
   string info = string.Format("姓名：{0}，年龄：{1}", this.name, this.age);
   if (this.children.Count != 0)
   {
    info += (this.children.Count == 1) ? "\r\n孩子：" : "\r\n孩子们：";
    foreach (var child in this.children)
     info += "\r\n" + child.ToString();
   }
   return info;
  }
 }

public partial class ChildForm : Form
 {
  public const int WM_COPYDATA = 0x004A;
  private IntPtr hostHandle = IntPtr.Zero;
  Person person = new Person("liujw", 1999);
  [DllImport("User32.dll", EntryPoint = "SendMessage")]
  private static extern int SendMessage(
   IntPtr hWnd,    // handle to destination window
   int Msg,     // message
   int wParam,    // first message parameter
   ref COPYDATASTRUCT lParam // second message parameter
  );
  public ChildForm(string[] args)
  {
   InitializeComponent();
   if (args.Length != 0)
    this.hostHandle = (IntPtr)int.Parse(args[0]);
  }
  private void btnSubmit_Click(object sender, EventArgs e)
  {
   this.person.Name = txtName.Text;
   int age;
   this.person.Age = int.TryParse(txtAge.Text, out age) ? age : 0;
   this.person.AddChildren();
   if (this.hostHandle != IntPtr.Zero)
   {
    string data = GetPersionStr();
    COPYDATASTRUCT cds = new COPYDATASTRUCT();
    cds.dwData = (IntPtr)901;
    cds.cbData = data.Length + 1;
    cds.lpData = data;
    SendMessage(this.hostHandle, WM_COPYDATA, 0, ref cds);
   }
  }
  private string GetPersionStr()
  {
   return JsonConvert.SerializeObject(this.person);
  }
 }

/// <summary>
  /// 应用程序的主入口点。
  /// </summary>
  [STAThread]
  static void Main(string[] args)
  {
   Application.EnableVisualStyles();
   Application.SetCompatibleTextRenderingDefault(false);
   Application.Run(new ChildForm(args));
  }

public partial class MainForm : Form
 {
  public const int WM_COPYDATA = 0x004A;
  public MainForm()
  {
   InitializeComponent();
  }
  protected override void WndProc(ref Message m)
  {
   base.WndProc(ref m);
   switch (m.Msg)
   {
    case WM_COPYDATA:
     COPYDATASTRUCT copyData = new COPYDATASTRUCT();
     Type type = copyData.GetType();
     copyData = (COPYDATASTRUCT)m.GetLParam(type);
     string data = copyData.lpData;
     RestorePerson(data);
     break;
   }
  }
  private void RestorePerson(string data)
  {
   var person = JsonConvert.DeserializeObject<Person>(data);
   if (person != null)
    txtInfo.Text = person.ToString();
  }
  private void btnSubmit_Click(object sender, EventArgs e)
  {
   RunChildProcess();
  }
  private void RunChildProcess()
  {
   string appPath = Path.GetDirectoryName(Application.ExecutablePath);
   string childPath = Path.Combine(appPath, "ChildApp.exe");
   Process.Start(childPath, this.Handle.ToString());
  }
 }

public static class SerializeHelper
 {
  /// <summary>
  /// 序列obj对象为base64字串
  /// </summary>
  /// <param name="obj"></param>
  /// <returns></returns>
  public static string Serialize(object obj)
  {
   if (obj == null)
    return string.Empty;
   try
   {
    var formatter = new BinaryFormatter();
    var stream = new MemoryStream();
    formatter.Serialize(stream, obj);
    stream.Position = 0;
    byte[] buffer = new byte[stream.Length];
    stream.Read(buffer, 0, buffer.Length);
    stream.Close();
    return Convert.ToBase64String(buffer);
   }
   catch (Exception ex)
   {
    throw new Exception(string.Format("序列化{0}失败，原因：{1}", obj, ex.Message));
   }
  }
  /// <summary>
  /// 反序列化字符串到对象
  /// </summary>
  /// <param name="str">要转换为对象的字符串</param>
  /// <returns>反序列化出来的对象</returns>
  public static T Deserialize<T>(string str)
  {
   var obj = default(T);
   if (string.IsNullOrEmpty(str))
    return obj;
   try
   {
    var formatter = new BinaryFormatter();
    byte[] buffer = Convert.FromBase64String(str);
    MemoryStream stream = new MemoryStream(buffer);
    obj = (T)formatter.Deserialize(stream);
    stream.Close();
   }
   catch (Exception ex)
   {
    throw new Exception(string.Format("序列化{0}失败，原因：{1}", obj, ex.Message));
   }
   return obj;
  }
 }