无法在C＃中通过.NET远程检索int属性

Question

I am having an issue with reading a property over a .NET remoting channel. Here is the beginning of my class:

[Serializable]
public class MachineID
{
    private string mySystemDeviceSerial = null;
    /// <summary>
    /// Returns the hard drive serial that Windows is installed on.
    /// </summary>
    public string SystemDeviceSerial
    {
        get { return mySystemDeviceSerial; }
    }

    private string mySystemName = null;
    /// <summary>
    /// Returns the current name of the system.
    /// </summary>
    public string SystemName
    {
        get { return mySystemName; }
    }

    private string myLastError = string.Empty;
    /// <summary>
    /// Returns the last error that occurred. Returns string.Empty if no error has occurred.
    /// </summary>
    public string LastError
    {
        get { return myLastError; }
    }

    private int myPort = -2;
    public int Port
    {
       get { return this.myPort; }
       set { this.myPort = value; }
    }

All properties are accessible just fine on the local machine. However, when I try to read the Port property from a client over a .NET remoting channel, I do not get the value that has been assigned to myPort, but rather, the initial value of -2. I am stumped on this, as the all of the string properties are able to be read fine. Any ideas? Am I not serializing this class properly?

It is worthy to note that all I have done to make this class and members serializable is add the [Serializable] attribute at the top of the class. I am not sure if this is the proper way to do this, so perhaps this could be a part of the issue?

Answer 1

My guess (and I stress it is just a guess) is that you have the order wrong- that you are

1. Retrieving an item from the remoting host
2. Updating it (on the host), then
3. Expecting the value in the client to be updated to the value you changed on the host.

When you use [Serializable] , you are turning the object into a byte stream, transmitting it over the wire to the remoting client, then reconstituting it into a new object on the client. That means that the client's copy is completely disconnected from the server's copy. If you want the client's copy to always show the updated values from the server (without re-transmitting the whole object), make it inherit from MarshalByRefObject like @Hans-Passant suggests. That makes the client copy a transparent proxy that queries the server each time you access one of it's properties.