winapi - SendMessage to TextBox Window Child in C++ not working -

char arbc[60]; cout << "message: "; cin.getline(arbc+'\0',sizeof(arbc)+1); system("pause"); postmessage(hwndch,wm_settext,(wparam)*arbc,0); 

so hwndch window child , child textbox, it's parent main window form. problem wm_settext isn't setting text of textbox string of characters. know it's not problem windowchild because wm_char outputs @ least 1 character in textbox. note: i'm modifying handles of process.

you cannot use postmessage wm_settext. that's synchronous message. problem greater when window in different process. system needs marshal text process process. cannot asynchronous message.

use sendmessage instead.

your other problems include @ least following:

• the wparam argument wrong. parameter ignored. pass (lparam)arbc lparam instead. documentation quite clear.
• you should not use c strings in case. use std::string, , c_str().
• your use of sizeof wrong. use of getline wrong too.
• you seem confused on function calling. title says sendmessage, code says postmessage.

you want along these lines:

std::cout << "message: "; std::string msg; std::getline(std::cin, msg); sendmessage(hwndch, wm_settext, 0, (lparam)msg.c_str());