Try & Error

I had a real pain recently where I wanted to control one windows app from another. I found some useful stuff on the net, but nothing that gave an end to end solution. So here’s what I came up with.

Firstly I’ll explain why this is useful. SendMessage is part of the Win32 API, and is used to send messages from one application to another. There are a set of predefined properties that the message can relate to, and these can be used to send messages to existing applications to perform all sorts of useful functions such as changing the font in notepad, or bringing a window to the fore. For more information of the wider use of the SendMessage function, have a look at:

http://www.autohotkey.com/docs/commands/PostMessage.htm

http://msdn.microsoft.com/en-us/library/ms644950(VS.85).aspx

The main use that I’m interested in is passing a specific instruction (via a string) from one app that I’ve written, to another one that I’ve written. This way I can effectively remote control one app from another (particularly useful if you want your main application to open a pop-up, and you don’t want to worry about the pop-up’s performance affecting the main application). Let’s now have a quick look at the SendMessage function:

SendMessage(int hWnd, int Msg, int wParam, int lParam)

hWnd – This is the window instance id of the application you want to send a message to. This id is retrieved using the FindWindow function

Msg – This is the type of message you want to send

wParam – Message specific data you pass in

wParam – Message specific data you pass in

Also used is the FindWindow function. This is to get the relevant window id:

FindWindow(String lpClassName, String lpWindowName)

lpClassName -The name of the class you want

lpWindowName – The name of the window that you want

To send a message that is a string, you need to use the WM_DATACOPY message property. The hard part is that you cannot just send the string as a parameter across. You need to send a pointer to the memory address of the string. If you just want to send an integer as a message you can use the WM_USER message property and send it as a value without a problem.

Below now is a brief listing of my MessageHelper.cs class, for the whole class file see:

http://craigcook.co.uk/samples/MessageHelper.cs.txt

So now you can call the code to send a message like so:

MessageHelper msg = new MessageHelper();
int result = 0;
//First param can be null
int hWnd = msg.getWindowId(null, “My App Name”);
result = msg.sendWindowsStringMessage(hWnd, 0, “Some_String_Message”);
//Or for an integer message
result = msg.sendWindowsMessage(hWnd, MessageHelper.WM_USER, 123, 456);

Now all you need to do on the app that you want to receive the message is override the following function in the form class (obviously you can change what the responses are, and you’ll need to create constants for the parameters):

출처 : http://boycook.wordpress.com/2008/07/29/c-win32-messaging-with-sendmessage-and-wm_copydata/

Spy++의 창 핸들을 찾는 방식을 어떻게 구현하나 뒤지다가 C++ 로 코드프로젝트에 만들어져 있는걸 보고,

C# 으로 만들어진 게 없나 하고 찾아봤는데..

역시나 있다..

만쉐~ 역시 선구자들은 많아.. 잘사용해보세~ -_-;

링크 : http://devpia.co.kr/MAEUL/Contents/Detail.aspx?BoardID=50&MAEULNO=20&no=881823&ref=881821&page=1

C++ 소스 링크 : http://www.codeproject.com/Articles/1698/MS-Spy-style-Window-Finder

C# 소스 링크 : http://www.codeproject.com/Articles/34981/FindWindow

MouseKeyboardLib2008.zip

원문 : http://www.codeproject.com/KB/system/globalmousekeyboardlib.aspx

물론 그냥 쌩으로 만들어 써도 되지만 , 이렇게 잘 정리되고 간단한 라이브러리를 쓰는것도 참 괜찮은 방법.

예제는 프로젝트를 열어보면 있다.

간단한 키보드 후킹 사용법 : 

            KeyboardSimulator.KeyDown(System.Windows.Forms.Keys.A);
            KeyboardSimulator.KeyUp(System.Windows.Forms.Keys.A);

유의점이라면 매개변수 'Keys' 는 윈폼의 것이다. 따라서 참조에 윈폼을 추가해야 한다.
그냥 WPF 로 바꿔도 무방하다만, WPF 만 할것도 아니고 XNA 도 있고 여러가지 상황을 생각한다면 
걍.. 이대로 쓰는것도 그리 불편하진 않다.

KeyValuePair 를 이용한다


            Dictionary<String, Object> dic = new Dictionary<String, object>();
            dic.Add("String0", true);
            dic.Add("String1", 13);

            foreach (KeyValuePair<String, Object> p in dic)
            {
                Console.WriteLine(p);
            }