/// <summary>
/// Constructor which creates the data gram from a message and channel name.
/// </summary>
/// <param name="channel">The channel through which the message will be sent.</param>
/// <param name="message">The string message to send.</param>
public DataGram(string channel, string message)
{
this.allocatedMemory = false;
this.dataStruct = new Native.COPYDATASTRUCT();
this.channel = channel;
this.message = message;
}
public void SendToChannel(string channelName, string message)
{
if (string.IsNullOrEmpty(channelName))
{
throw new ArgumentNullException(channelName, "The channel name must be defined");
}
if (message == null)
{
throw new ArgumentNullException(message, "The messsage packet cannot be null");
}
if (string.IsNullOrEmpty(channelName))
{
throw new ArgumentException("The channel name may not contain the ':' character.", "channelName");
}
// create a DataGram instance, and ensure memory is freed
using (DataGram dataGram = new DataGram(channelName, message))
{
// Allocate the DataGram to a memory address contained in COPYDATASTRUCT
Native.COPYDATASTRUCT dataStruct = dataGram.ToStruct();
// Use a filter with the EnumWindows class to get a list of windows containing
// a property name that matches the destination channel. These are the listening
// applications.
WindowEnumFilter filter = new WindowEnumFilter(XDListener.GetChannelKey(channelName));
WindowsEnum winEnum = new WindowsEnum(filter.WindowFilterHandler);
foreach (IntPtr hWnd in winEnum.Enumerate())
{
IntPtr outPtr = IntPtr.Zero;
// For each listening window, send the message data. Return if hang or unresponsive within 1 sec.
Native.SendMessageTimeout(hWnd, Native.WM_COPYDATA, IntPtr.Zero, ref dataStruct, Native.SendMessageTimeoutFlags.SMTO_ABORTIFHUNG, 1000, out outPtr);
}
}
}
/// <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;
}
}
