/// <summary>
/// The native window message filter used to catch our custom WM_COPYDATA
/// messages containing cross AppDomain messages. All other messages are ignored.
/// </summary>
/// <param name="msg">A representation of the native Windows Message.</param>
protected override void WndProc(ref Message msg)
{
base.WndProc(ref msg);
if (msg.Msg == Native.WM_COPYDATA)
{
// we can free any unmanaged resources immediately in the dispose, managed channel and message
// data will still be retained in the object passed to the event
using (DataGram dataGram = DataGram.FromPointer(msg.LParam))
{
if (MessageReceived != null && dataGram.IsValid)
{
MessageReceived.Invoke(this, new XDMessageEventArgs(dataGram));
}
}
}
}
/// <summary>
/// Constructor creates an instance of the class from a pointer address, and expands
/// the data packet into the originating channel name and message.
/// </summary>
/// <param name="lpParam">A pointer the a COPYDATASTRUCT containing information required to
/// expand the DataGram.</param>
private DataGram(IntPtr lpParam)
{
this.allocatedMemory = false;
this.dataStruct = (Native.COPYDATASTRUCT)Marshal.PtrToStructure(lpParam, typeof(Native.COPYDATASTRUCT));
byte[] bytes = new byte[this.dataStruct.cbData];
Marshal.Copy(this.dataStruct.lpData, bytes, 0, this.dataStruct.cbData);
string rawmessage;
using (MemoryStream stream = new MemoryStream(bytes))
{
BinaryFormatter b = new BinaryFormatter();
rawmessage = (string)b.Deserialize(stream);
}
// use helper method to expand the raw message
using (DataGram dataGram = DataGram.ExpandFromRaw(rawmessage))
{
this.channel = dataGram.Channel;
this.message = dataGram.Message;
}
}
/// <summary>
/// Constructor used to create a new instance from a DataGram struct.
/// </summary>
/// <param name="dataGram">The DataGram instance.</param>
internal XDMessageEventArgs(DataGram dataGram)
{
this.dataGram = dataGram;
}
/// <summary>
/// Constructor used to create a new instance from a DataGram struct.
/// </summary>
/// <param name="dataGram">The DataGram instance.</param>
internal XDMessageEventArgs(DataGram dataGram)
{
this.dataGram = dataGram;
}