An application sends a WM_GETTEXT message to copy the text that corresponds to a window into a buffer provided by the caller.
WM_GETTEXT
wParam = (WPARAM) cchTextMax; // number of characters to copy
lParam = (LPARAM) lpszText; // address of buffer for text
The return value is the number of characters copied.
The DefWindowProc function copies the text associated with the window into the specified buffer and returns the number of characters copied.
For an edit control, the text to be copied is the content of the edit control. For a combo box, the text is the content of the edit control (or static-text) portion of the combo box. For a button, the text is the button name. For other windows, the text is the window title. To copy the text of an item in a list box, an application can use the LB_GETTEXT message.
When the WM_GETTEXT message is sent to a static control with the SS_ICON style, a handle to the icon will be returned in the first four bytes of the buffer pointed to by lpszText. This is true only if the WM_SETTEXT message has been used to set the icon.
In a rich edit control, if the text to be copied exceeds 64K, use either the message EM_STREAMOUT or EM_GETSELTEXT.
Windows NT: Requires version 3.1 or later.
Windows: Requires Windows 95 or later.
Windows CE: Requires version 1.0 or later.
Header: Declared in winuser.h.
Windows Overview, Window Messages, DefWindowProc, EM_GETSELTEXT, EM_STREAMOUT, GetWindowText, GetWindowTextLength, LB_GETTEXT, WM_GETTEXTLENGTH, WM_SETTEXT