Now, Delphi has been very easy to use multi-threaded up!

Look at a non-multithreaded example, other operations can not be performed (such as form drag) when the code is executed:

{ Custom method: drawing on the form ... } 
Procedure MyMethod;
 var 
  I: Integer; 
the begin 
  for I: = 0  to  500000  do 
  the begin 
    Form1.Canvas.Lock; 
    Form1.Canvas.TextOut ( 10 , 10 , the IntToStr ( I)); 
    Form1.Canvas.Unlock; 
  End ;
 End ; 

{ calling custom method above } 
Procedure TForm1.Button1Click (Sender: TObject);
 the begin 
  MyMethod; 
End ;

Amended as multithreading (modify only one line of code):

procedure MyMethod;
var
  i: Integer;
begin
  for i := 0 to 500000 do
  begin
    Form1.Canvas.Lock;
    Form1.Canvas.TextOut(10, 10, IntToStr(i));
    Form1.Canvas.Unlock;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  TThread.CreateAnonymousThread(MyMethod).Start; //!!!
end;

Code analysis: 

1, TThread now adds a lot of class method (direct method by the class name called), TThread.CreateAnonymousThread () is a more useful. 

2, as the name suggests, CreateAnonymousThread is to establish an anonymous thread object, its argument is that we need a method executed in a thread 

3, but the thread is suspended CreateAnonymousThread established, it needs to manually run; the Start the latter method is used to wake up the thread. 

4, (formerly) wake up threads or a method may be used Resume suspended properties (Suspended: = False;); but they are about to be abandoned, should now use start to start the thread.

---

The parameter type is CreateAnonymousThread TProc anonymous methods (reference), so the code can be abbreviated as:

Procedure TForm1.Button1Click (Sender: TObject);
 the begin 
  TThread.CreateAnonymousThread ( // direct write method body 
    Procedure 
    var 
      I: Integer; 
    the begin 
      for I: = 0  to  500000  do 
      the begin 
        Canvas.Lock; 
        Canvas.TextOut ( 10 , 10 , the IntToStr (I)); 
        Canvas.Unlock; 
      End ;
     End  // here no semicolon 
  ) .Start;
 End ;

Delay Execution:

var
  myThread: TThread;

procedure TForm1.FormCreate(Sender: TObject);
begin
  myThread := TThread.CreateAnonymousThread(
    procedure
    var
      i: Integer;
    begin
      for i := 0 to 500000 do
      begin
        Canvas.Lock;
        Canvas.TextOut(10, 10, IntToStr(i));
        Canvas.Unlock;
      end;
    end
  );
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  myThread.Start;
end;