/// <summary>
/// Override for a form's Window Procedure to handle WM_COPYDATA
/// messages sent by other instances of this class.
/// </summary>
/// <param name="m">The Windows Message information.</param>
protected override void WndProc(ref System.Windows.Forms.Message m)
{
if (m.Msg == WM_COPYDATA)
{
COPYDATASTRUCT cds = new COPYDATASTRUCT();
cds = (COPYDATASTRUCT)Marshal.PtrToStructure(m.LParam, typeof(COPYDATASTRUCT));
if (cds.cbData > 0)
{
byte[] data = new byte[cds.cbData];
Marshal.Copy(cds.lpData, data, 0, cds.cbData);
MemoryStream stream = new MemoryStream(data);
BinaryFormatter b = new BinaryFormatter();
CopyDataObjectData cdo = (CopyDataObjectData)b.Deserialize(stream);
if (channels.Contains(cdo.Channel))
{
DataReceivedEventArgs d = new DataReceivedEventArgs(cdo.Channel, cdo.Data, cdo.Sent);
OnDataReceived(d);
m.Result = (IntPtr)1;
}
}
}
else if (m.Msg == WM_DESTROY)
{
// WM_DESTROY fires before OnHandleChanged and is
// a better place to ensure that we've cleared
// everything up.
channels.OnHandleChange();
base.OnHandleChange();
}
base.WndProc(ref m);
}
/// <summary>
/// Sends the specified object on this channel to any other
/// applications which are listening. The object must have the
/// SerializableAttribute set, or must implement ISerializable.
/// </summary>
/// <param name="obj">The object to send</param>
/// <returns>The number of recipients</returns>
public int Send(object obj)
{
int recipients = 0;
if (disposed)
{
throw new InvalidOperationException("Object has been disposed");
}
if (recreateChannel) // handle has changed
{
addChannel();
}
CopyDataObjectData cdo = new CopyDataObjectData(obj, channelName);
// Try to do a binary serialization on obj.
// This will throw and exception if the object to
// be passed isn't serializable.
BinaryFormatter b = new BinaryFormatter();
MemoryStream stream = new MemoryStream();
b.Serialize(stream, cdo);
stream.Flush();
// Now move the data into a pointer so we can send
// it using WM_COPYDATA:
// Get the length of the data:
int dataSize = (int)stream.Length;
if (dataSize > 0)
{
// This isn't very efficient if your data is very large.
// First we copy to a byte array, then copy to a CoTask
// Mem object... And when we use WM_COPYDATA windows will
// make yet another copy! But if you're talking about 4K
// or less of data then it doesn't really matter.
byte[] data = new byte[dataSize];
stream.Seek(0, SeekOrigin.Begin);
stream.Read(data, 0, dataSize);
IntPtr ptrData = Marshal.AllocCoTaskMem(dataSize);
Marshal.Copy(data, 0, ptrData, dataSize);
// Enumerate all windows which have the
// channel name, send the data to each one
EnumWindows ew = new EnumWindows();
ew.GetWindows();
// Send the data to each window identified on
// the channel:
foreach (EnumWindowsItem window in ew.Items)
{
if (!window.Handle.Equals(this.owner.Handle))
{
if (GetProp(window.Handle, this.channelName) != 0)
{
COPYDATASTRUCT cds = new COPYDATASTRUCT();
cds.cbData = dataSize;
cds.dwData = IntPtr.Zero;
cds.lpData = ptrData;
int res = SendMessage(window.Handle, WM_COPYDATA, (int)owner.Handle, ref cds);
recipients += (Marshal.GetLastWin32Error() == 0 ? 1 : 0);
}
}
}
// Clear up the data:
Marshal.FreeCoTaskMem(ptrData);
}
stream.Close();
return(recipients);
}