Learn message (16): Test message $0118

Current understanding of message $0118:

1. Neither Microsoft nor Delphi have defined a constant for the modified message. It is more appropriate to use wm_systimer imer if it is defined;

2. This message is sent only when the focus is obtained by text input controls (such as tmemo, trichedit, and tedit) to control the input cursor;

3. The message is synchronized with the input cursor once per second;

4. Once the message reaches its purpose, it is returned immediately. Therefore, the message method, wndproc, dispatch, and even defaulthandler cannot respond;

5. Because application. processmessages first sends the message to application. onmessage, onmessage can be received.

In this example:

Code File:

Unit unit1; interfaceuses windows, messages, sysutils, variants, classes, graphics, controls, forms, dialogs, stdctrls, comctrls, appevets; Type tform1 = Class (tform) button1: tbutton; button2: tbutton; applicationevents1: tapplicationevents; Procedure button1click (Sender: tobject); Procedure applicationevents1message (var msg: tagmsg; var handled: Boolean); end; var form1: tform1; implementation {$ R *. DFM} procedure tform1.applicationevents1message (var msg: tagmsg; var handled: Boolean); begin if MSG. message = $0118 then begin text: = timetostr (now); end; Procedure tform1.button1click (Sender: tobject); const W = 150; H = 50; L = 10; vaR T: integer; begin T: = L; with tmemo. create (Self) Do begin parent: = self; text: = classname; width: = W; Height: = H; left: = L; top: = T; Inc (t, H + l); end; with trichedit. create (Self) Do begin parent: = self; text: = classname; width: = W; Height: = H; left: = L; top: = T; Inc (t, H + l); end; with tedit. create (Self) Do begin parent: = self; text: = classname; width: = W; // Height: = H; left: = L; top: = T; // Inc (T, H + l); end; text: = 'current text input control has no focal point'; button1.enabled: = false; end.
 
   
 

Form file:

 
Object form1: tform1 left = 0 Top = 0 caption = 'form1' clientheight = 165 clientwidth = 320 color = clbtnface font. charset = default_charset font. color = clwindowtext font. height =-11 font. name = 'tahoma 'font. style = [] oldcreateorder = false pixelsperinch = 96 textheight = 13 object button1: tbutton left = 176 Top = 32 width = 136 Height = 25 caption = #24314 #31435 #20960 #20010 #25991 #26412 #36755 #20837 #25511 #20214 # taborder = 0 onclick = button1click end object button2: tbutton left = 176 Top = 83 width = 136 Height = 25 caption = #25226 #28966 #28857 #36716 #31227 #21040 #27492 taborder = 1 end object applicationevents1: tapplicationevents onmessage = applicationevents1message left = 136 Top = 64 endend