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DELPI 5 + NEED HELP GUYS Sendin command to anotha applicaton

Guys, is it possible to send a command to anotha application? in Delphi...how?
and is it possible to trace changes in anotha application?
1 Solution
yes there are severeal possibilities to send commands to other applications.
You can make a api sendMessage if you have the handle of the other application
You can implement a COM interface in the other application.
You can open a TCP/IP or UDP socket on the other connection
to determine what will be right fitting it would be nessesary to know what you are planning to do.

tracing changes in another application? I am not sure what you mean ...

you can exchange commands or data between two or more applications by using windows messages, but that should be prepared in the two applications, I mean if u send a message from one application to another, the recpient application should accept capturing messages...
or u can build a connection socket, and make a connection channel between the two aplications through the socket.
KaspyAuthor Commented:
Hhmmm...guys thx again for ur attention....
i tried Postmessage ....but i constantly recieve error...
I can't prepare anotha application to recieve my commands...:( umm...i try to explain a bit more....like if i click on otha application n type anytin n press enter:) ...this leads to exucution or failure of the command...and i'm askin how can i make my program to do this?
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KaspyAuthor Commented:
and by tracin..i meant...like if i finally sent command and it worked...program responds...n can my program get that respond somehow?
KaspyAuthor Commented:
sendmessage(findwindow(nil,'name', "CTRL+N",0,0));
i get error here....tried without ""..tried everything:) doesn't work:(
well you are completly out of syntax:
1. " is not a valid character for quoting in object pascal you can use ' only
2. find window is declared as
HWND FindWindow(

    LPCTSTR lpClassName,     // pointer to class name
    LPCTSTR lpWindowName      // pointer to window name



Points to a null-terminated string that specifies the class name or is an atom that identifies the class-name string. If this parameter is an atom, it must be a global atom created by a previous call to the GlobalAddAtom function. The atom, a 16-bit value, must be placed in the low-order word of lpClassName; the high-order word must be zero.


Points to a null-terminated string that specifies the window name (the window's title). If this parameter is NULL, all window names match.

you try to pass 4 parameters into it

3. SendMessage is defined as
LRESULT SendMessage(

    HWND hWnd,     // handle of destination window
    UINT Msg,     // message to send
    WPARAM wParam,     // first message parameter
    LPARAM lParam      // second message parameter



Identifies the window whose window procedure will receive the message. If this parameter is HWND_BROADCAST, the message is sent to all top-level windows in the system, including disabled or invisible unowned windows, overlapped windows, and pop-up windows; but the message is not sent to child windows.


Specifies the message to be sent.


Specifies additional message-specific information.


Specifies additional message-specific information.

you pass only one parameter

To change the Capion of another application you could do the following:
  hWindow , hControl: Thandle;
  str: PChar;
  hWindow := findwindow(nil,'NameOfTheForm');
  sendmessage(hWindow, WM_SETTEXT,0,Integer(StrPCopy(str,'my new Caption')));

If you want to set any text in a control of this window, you need the Handle of the control, not of the form.

The easiest way to retrieve them is if you prepare the "other" application with reacting to custom user messages wich may return the needed control handle.

belonging the tracing : SendMessage gives you a result dependent on the message you sent.

in my example the SDK help says it returnes :
"The return value is TRUE if the text is set. It is FALSE (for an edit control), LB_ERRSPACE (for a list box), or CB_ERRSPACE (for a combo box) if insufficient space is available to set the text in the edit control. It is CB_ERR if this message is sent to a combo box without an edit control."

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