TdxVisualRefinements.BeginUpdate Method

Postpones all control redraw operations that reflect global padding changes until an EndUpdate procedure is called.

Declaration

class procedure BeginUpdate; static;

Remarks

Every time a HeaderPadding, Padding, LightBorders, or UsePaddingForStandaloneEditors property value changes, all affected DevExpress controls redraw themselves to reflect the change. Enclose multiple global visual changes between BeginUpdate and EndUpdate procedure calls to avoid excessive redraw operations.

BeginUpdate/EndUpdate and Batch Changes

A BeginUpdate procedure call disables notifications and postpones all changes until an EndUpdate call. A subsequent EndUpdate call does the following:

• Re-enables change notifications and the corresponding redraw operations
• Applies all changes made after a BeginUpdate call
• Sends the corresponding notifications in a batch
• Redraws all affected DevExpress controls

Note

Ensure that every BeginUpdate procedure call is followed by an EndUpdate call, even if an exception occurs. Otherwise, your application’s UI remains frozen and unresponsive.

Code Example: Apply Custom Padding to All Editors

The code example in this section adds 5 pixels to left and right paddings, and 2 pixels to top and bottom paddings in container controls and standalone editors.

Open the Project Source to Edit the Main Function

To open the main application unit of your project, you can use one of the following options:

• Select Project → View Source in the main menu of your RAD Studio IDE.
• Select the target project in the Projects Window and press Ctrl + V (alternatively, you can display the context menu and select the View Source option).

Delphi

uses
  Forms,
  cxLookAndFeels, // Adds the cxLookAndFeels unit to use the TdxVisualRefinements class
// ...
begin
  TdxVisualRefinements.BeginUpdate;  // Initiates the following batch change
  try
    TdxVisualRefinements.Padding := Rect(5, 2, 5, 2);
    TdxVisualRefinements.UsePaddingForStandaloneEditors := True;
  finally
    TdxVisualRefinements.EndUpdate;  // Calls EndUpdate regardless of the batch operation's success
  end;
  Application.Initialize;
  Application.MainFormOnTaskbar := True;
  Application.CreateForm(TMyForm, MyForm);
  Application.Run;
end.

C++

#include <vcl.h>
#include "cxLookAndFeels.hpp"  // Adds the cxLookAndFeels unit to use the TdxVisualRefinements class
#pragma hdrstop
#include <tchar.h>
//---------------------------------------------------------------------------
USEFORM("Unit1.cpp", Form1);
//---------------------------------------------------------------------------
int WINAPI _tWinMain(HINSTANCE, HINSTANCE, LPTSTR, int)
{
  TdxPadding APadding;

  APadding.Left = 5;
  APadding.Top = 2;
  APadding.Right = 5;
  APadding.Bottom = 2;

    try
    {
      TdxVisualRefinements::BeginUpdate();  // Initiates the following batch change
      try
      {
        TdxVisualRefinements::Padding = APadding;
        TdxVisualRefinements::UsePaddingForStandaloneEditors = true;
      }
      __finally
      {
        TdxVisualRefinements::EndUpdate();  // Calls EndUpdate regardless of the batch operation's success
      }

      Application->Initialize();
      Application->MainFormOnTaskBar = true;
      Application->CreateForm(__classid(TMyForm), &MyForm);
      Application->Run();
    }
    // ...