Question

I would like to know where is the formshow in delphi 2010 as when I can only see a formcreate in my project.

The reason I am asking is because I need to add Randomize in the FormShow event handler, as shown below:

procedure TfrmWinnaSpree.FormShow(Sender: TObject);
begin
  Randomize;
end;

Answer 1

You create the event handler the same way you create almost every event handler in Delphi, by double-clicking the method in the Events tab of the Object Inspector.

Click on the form itself (not any control on the form), then switch to the Object Inspector. Click on the Events tab, and then scroll down to the OnShow event. Double-click in the right half next to the event name, and the IDE will create a new, empty event handler and put the cursor in the right place to start writing code.

procedure TForm3.FormShow(Sender: TObject);
begin
  |
end;

However, FormShow is the wrong place to call Randomize, because FormShow executes every time your form is shown, and that can happen more than once. Here’s an example (it assumes two forms, Form1 and Form2, autocreated as usual in the .dpr file with the default variable names, which of course is a bad idea – this is to demonstrate a problem with your question’s purpose):

procedure TForm2.FormShow(Sender: TObject);
begin
  ShowMessage('In FormShow');
end;


procedure TForm1.Button1Click(Sender: TObject);
begin
  Form2.Visible := not Form2.Visible;
end;

Run the program and click TForm1.Button1 multiple times; you’ll see the In FormShow message every other time you do so.

The proper places for a call to Randomize are:

• in your main form’s FormCreate

• in an initialization section of your main form’s unit

  unit uMainForm;
  
  interface
  
    ...
  
  implementation
  
    ...
  
  initialization 
  
  Randomize;
  
  end.
  

• in your project source (.dpr) file

  program MyGreatApp;
  
  uses
    Math,
    Vcl.Forms,
    uMainForm in 'uMainForm.pas' {Form1};
  
    {$R *.RES}
  
  begin
    Randomize;
    Application.Initialize;
    Application.MainFormOnTaskbar := True;
    Application.Title := 'My Super App';
    Application.CreateForm(TForm1, Form1);
    Application.Run;
  end.