Messages message uses the

Example 1UnitUnit1;Interface usesWindows, Messages, sysutils, variants, Classes, Graphics, Controls, Forms, Dialogs, Stdctrls; ConstWm_me=wm_user+ -;//custom messages; typeTForm1=class(Tform) Button1:tbutton;procedureButton1Click (sender:tobject);//The first type of message processing, only constant messages can be processed ;    procedureWmme (var message: Tmessage);messageWm_me;//custom message processing, specialized in handling Wm_me messages; private   {Private Declarations}  Public{Public Declarations}//The second type of message processing, which can handle constant or variable messages;procedureWndProc (var message: Tmessage);Override;//Reload window message procedure//The third method of message processing    procedureWmcommand (varMessage:twmcommand);messageWm_command;//command Message handling procedures    procedureWmsyscommand (varMsg:twmsyscommand);messageWm_syscommand;//processing of systematic messages; End;varForm1:tform1;Implementation{$R *.DFM} procedureTform1.button1click (sender:tobject);beginSendMessage (Handle,wm_me,0,0);//send the message wm_me, the message is first handled by WndProc, and then handed to wmme processing;End; procedureTform1.wmsyscommand (varMsg:twmsyscommand);begin  //the code below is for the user to hide the form if they click the Minimize and Close button on the title bar.   if(msg.cmdtype=sc_minimize)or(Msg.cmdtype=sc_close) Then  beginSelf.hide; End ElseDefaultHandler (MSG);//The purpose of this sentence is to continue to deal with other information;End; procedureTform1.wmcommand (varMessage:twmcommand);begin     //The third method of message processingifMessage.notifycode = bn_clicked ThenifFindControl (message.ctl) = Button1 Thenshowmessage (' Click on Button1 ');inherited;End; procedureTform1.wmme (var message: tmessage);beginShowMessage (IntToStr (Handle)+'Wmme');//The first method of message processingEnd; procedureTform1.wndproc (var message: tmessage);begin   if message. Msg=wm_me Then //The second method of message processingShowMessage (IntToStr (Handle) +'WndProc'); inheritedWndProc (Message);//here inherited will trigger a wmme message;End;End. Example 2/////////////////////////////////////////////////////////////the way messages are broadcast///////////////////////////////////////// ///////////////////////////////////////////message broadcasts can only deliver messages to the main program that receives messages, MDIChild forms cannot receive broadcast messages;/////////UnitUnit1;InterfaceusesWindows, Messages, sysutils, variants, Classes, Graphics, Controls, Forms, Dialogs, Stdctrls;typeTForm1=class(tform) Button1:tbutton; procedureButton1Click (Sender:tobject); procedureformcreate (sender:tobject);Private    {Private Declarations}  Public    {Public Declarations}    procedureWndProc (var message: Tmessage);Override; End;varForm1:tform1; Mymessage:dword;Implementation{$R *.DFM}{TForm1}procedureTform1.wndproc (var message: tmessage);begin if message. Msg=mymessage Then //3rd Step: Reload the Windows message processing process, processing the received mymessage message;ShowMessage (Floattostr (Handle) +'Mymessage'); inheritedWndProc (Message);End; procedureTform1.button1click (sender:tobject);beginSendMessage (Hwnd_broadcast,mymessage,0,0);//2nd step: Broadcast Mymessage news;End;/////////Pre-registration of Windows messages; The first method////////////////////proceduretform1.formcreate (sender:tobject);begin //The same string, such as ' Mymessageme ', is returned with the same mymessage result when the RegisterWindowMessage registration message is called in a different program. This provides the possibility of broadcasting messages between different programs. That is, when different programs register messages, you must register the same string of characters. Mymessage:=registerwindowmessage ('Mymessageme');//1th Step: Registering Windows messages, focusing on the value returned MymessageEnd;/////////Pre-registration of Windows messages; the second method////////////////////{initialization mymessage:=registerwindowmessage (' Mymessageme ');}  //Broadcastsystemmessage, you can broadcast messages between processes;procedureTform1.sendsmsmessage;varsmsmessage:cardinal; recipt:cardinal;begin TrySmsmessage:=registerwindowmessage ('Sendsmsmessage'); Recipt:=bsm_alldesktops;//so all desktop programs can receiveBroadcastsystemmessage (Bsf_postmessage, @recipt, Smsmessage,0,0); except End;End; End.

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Messages message uses the