Delphi Programming Diary - Jitendra Kumar

One time I was discussing with a .Net programmer about static variables. Then I tried to declared a static variable in Delphi. But I could not. Because there no keyword 'Static' in Delphi. So I searched found 'Typed Constant' which act as static variable in Delphi. By default Delphi doesn't allow static variables, it only allows static methods, functions and properties.  But we can use typed constant to declare a static variable in Delphi.  That will work as like static variable in C#  that keep their value between routine calls. But this facility was available in Delphi 16 bit version i.e in Delphi 1 which is disappeared in Delphi 32 version. But for backward compatibility still Delphi has an option 'Assignable Typed Constant' option in compiler tab of project option. Project Menu -> Option -> Compiler Tab ->  Assignable Typed Constant  You need to check this option for use such facility else you will get following error. "[Error] Unit1.pas(30...

Refresh  - Repaints the control on the screen. Call Refresh method to repaint the control immediately. Refresh calls the Repaint method. Use the Refresh and Repaint methods interchangeably. Repaint  - Forces the control to repaint its image on the screen. Call Repaint to force the control to repaint its image immediately. If the ControlStyle property includes csOpaque, the control paints itself directly. Otherwise, the Repaint method calls the Invalidate method and then the Update method so that any visible portions of controls beneath the control will be repainted as well. Update  - Processes any pending paint messages immediately. Call Update to force the control to be repainted before any more, possibly time-consuming, processing takes place. Use Update to provide immediate feedback to the user that cannot wait for the Windows paint message to arrive. Update does not invalidate the control, but simply forces a repaint of any regions that have already been invalidated. ...