Why change the window size, will trigger a WM_SIZE message??????
The use of the Delphi keyword message???
How to define their own news??

 unit Form1Unit; 

Interface 

USES the 
Windows, Messages, SysUtils, Variants, Classes, Graphics, 
Controls, Forms, StdCtrls; 

Type 
TForm1=class (TForm) 
For: TButton; 
Procedure Button1Click (Sender: TObject); 
Private 
{Private declarations} 
Procedure Refresh (var Msg: TMessage); The message WM_SIZE; 
Public 
{Public declarations} 
end; 

Var 
Form1: TForm1; 

Implementation 

{$R *. DFM} 

{this method the news of the capture window size was changed} 
Procedure TForm1. Refresh (var Msg: TMessage); 
The begin 
{to the size of the window display in the title bar} 
Caption:=IntToStr (Width) + '-' + IntToStr (Height); 
{to invoke the default message handler, redrawn window} 
Inherited; 
end; 

{random to resize the window} 
Procedure TForm1. Button1Click (Sender: TObject); 
Var 
Size: Integer; 
The begin 
{button itself will be moved to the left upper corner of the window first, lest the narrow window after obscured} 
(Sender as TButton). Left:=0; 
(Sender as TButton). Top:=0; 

{get a random number, can be positive or negative} 
Randomize. 
Size: the Random=(100) - 50; 
{new Settings window size} 
The Width: the Width=+ Size; 
Height: Height=+ Size; 
{when change the window size, will trigger a WM_SIZE message, thus invoking we define TForm1. Refresh} 
end; 

End. 

CodePudding user response:

Intercept the message definition method:
Procedure of custom method name (var Msg: TMessage); The message to intercept the message constants;

When you want to intercept a message, simply structure declaration according to the above method can.
Such as mobile message response method named:
Procedure CustMove (var Msg: TMessage); The message WM_MOVE;


Why change the window size, will trigger a WM_SIZE message??????
The use of the Delphi keyword message???
How to define their own news??
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If I have some questions to continue to post:)

CodePudding user response:

First look at Windows message mechanism, and then look like the VCL structure analysis,

CodePudding user response:

The Refresh OnResize event is that you write

CodePudding user response:

Problem a: this is a Windows system running rules, is not decided by the Delphi,
News is actually an integer, than WM_USER can serve as a custom message,