What's the easiest way to write a please wait screen with Delphi?

Question

I just want a quick and dirty non-modal, non-closable screen that pops up and goes away to make 2 seconds seem more like... 1 second. Using 3-5 lines of code.

Answer 1

I usually add a form to the project, like this:

dfm:

object WaitForm: TWaitForm
  Left = 0
  Top = 0
  AlphaBlend = True
  AlphaBlendValue = 230
  BorderIcons = []
  BorderStyle = bsNone
  Caption = 'Please wait...'
  ClientHeight = 112
  ClientWidth = 226
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  Position = poMainFormCenter
  OnCloseQuery = FormCloseQuery
  PixelsPerInch = 96
  TextHeight = 13
  object Panel1: TPanel
    Left = 0
    Top = 0
    Width = 226
    Height = 112
    Align = alClient
    BevelInner = bvLowered
    Caption = 'Please wait...'
    Color = clSkyBlue
    ParentBackground = False
    TabOrder = 0
  end
end

while unit looks like this:

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ExtCtrls, StdCtrls;

type
  TWaitForm = class(TForm)
    Panel1: TPanel;
    procedure FormCloseQuery(Sender: TObject; var CanClose: Boolean);
  private
    { Private declarations }
    FCanClose: Boolean;
  public
    { Public declarations }
    class function ShowWaitForm: TWaitForm;
    procedure AllowClose;
  end;

var
  WaitForm: TWaitForm;

implementation

{$R *.dfm}

{ TWaitForm }

procedure TWaitForm.AllowClose;
begin
  FCanClose := True;
end;

procedure TWaitForm.FormCloseQuery(Sender: TObject; var CanClose: Boolean);
begin
  CanClose := FCanClose;
end;

class function TWaitForm.ShowWaitForm: TWaitForm;
begin
  Result := Self.Create(Application);
  Result.Show;
  Result.Update;
end;

end.

you call it like this:

procedure TForm2.Button1Click(Sender: TObject);
var
  I: Integer;
begin
  with TWaitForm.ShowWaitForm do
    try
      for I := 1 to 100 do
        Sleep(30);
    finally
      AllowClose;
      Free;
    end;
end;

just an idea, refinements is up to you.