一个关于GetTextBuf的问题？

Question

procedure TForm1.Button1Click(Sender: TObject);
var
  MyBuffer:Pchar;
  MyBufSize:Integer;
begin
//Form1.SetBounds(20,20,20,20);
         MyBufSize:=Button1.GetTextLen;
         Button1.GetTextBuf(MyBuffer,MyBufSize);//执行时出错。Why????
         StatusBar1.SetTextBuf(MyBuffer);
end;

Answer 1

因为你没给MyBuffer分配空间。GetTextBuf不会自动给那个缓冲区分配空间的，要求用户事先分好。解决办法:
procedure TForm1.Button1Click(Sender: TObject);
var
MyBuffer:Pchar;
MyBufSize:Integer;
begin
//Form1.SetBounds(20,20,20,20);
MyBufSize:=Button1.GetTextLen;GetMem(MyBuffer,MyBufSize+1); //给MyBuffer分配空间Button1.GetTextBuf(MyBuffer,MyBufSize);//执行时出错。Why????
StatusBar1.SetTextBuf(MyBuffer);FreeMem(MyBuffer, MyBufSize+1);{Frees memory allocated to MyBuffer}end;