private void bnSendMessage_Click(object sender, EventArgs e)
{
int nNumber;
// Validate the parameter value in tbNumber
if (!int.TryParse(this.tbNumber.Text, out nNumber))
{
MessageBox.Show("Invalid value of nNumber!");
return;
}
/////////////////////////////////////////////////////////////////
// Find the target Window Handle.
//
IntPtr hTargetWnd = WindowNative.FindWindow(null, "CSReceiveWM_COPYDATA");
// Validate the Window Handle.
if (hTargetWnd == IntPtr.Zero)
{
MessageBox.Show("Unable to find the target Window!");
return;
}
/////////////////////////////////////////////////////////////////
// Prepare the COPYDATASTRUCT struct with the data to be sent.
//
// Declare the MyStruct struct to hold the message
MyStruct myStruct;
myStruct.nNumber = nNumber;
myStruct.strMessage = this.tbMessage.Text;
// Marshals from the managed object to a native block of memory
IntPtr ptrMyStruct = Marshal.AllocHGlobal(Marshal.SizeOf(myStruct));
Marshal.StructureToPtr(myStruct, ptrMyStruct, true);
// Declare the COPYDATASTRUCT struct for the WM_COPYDATA message.
COPYDATASTRUCT cds = new COPYDATASTRUCT();
cds.cbData = Marshal.SizeOf(myStruct);
cds.lpData = ptrMyStruct;
/////////////////////////////////////////////////////////////////
// Send the COPYDATASTRUCT struct through the WM_COPYDATA message
// to the receiving Window.
//
// Send the WM_COPYDATA message
// The application must use SendMessage, instead of PostMessage
// to send WM_COPYDATA because the receiving application must
// accept while it is guaranteed to be valid.
WindowNative.SendMessage(
hTargetWnd, // Handle of the target Window
WindowNative.WM_COPYDATA, // WM_COPYDATE message
this.Handle, // Handle of the current Window
ref cds // COPYDATASTRUCT structure
);
// Check error of SendMessage
int result = Marshal.GetLastWin32Error();
if (result != 0)
{
MessageBox.Show(String.Format(
"SendMessage failed w/err 0x{0:X}", result));
}
/////////////////////////////////////////////////////////////////
// Clean up.
//
// Frees the native memory allocated for MyStruct
Marshal.FreeHGlobal(ptrMyStruct);
}