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inno-setuppascalscript

How do you determine if an object has be constructed in Inno Setup Pascal Script?


How do I check that my checkbox has been created / constructed and can be used to check if checked?

[Code]

var
  MyCheckBoxThatMayExistOrNot: TNewCheckBox;

procedure Whatever();
begin
  { Check if MyCheckBoxThatMayExistOrNot exists and checked }
  if ????? and MyCheckBoxThatMayExistOrNot.Checked then
  begin
    ...
  end;
end;

TIA!!


Solution

  • Compare the variable value against nil:

    if (MyCheckBoxThatMayExistOrNot <> nil) and
       MyCheckBoxThatMayExistOrNot.Checked then
    

    An equivalent is use of Assigned function:

    if Assigned(MyCheckBoxThatMayExistOrNot) and
       MyCheckBoxThatMayExistOrNot.Checked then
    

    You might want to explicitly initialize the variable to nil in InitializeSetup or InitializeWizard, but it should not be necessary: Are global variables in Pascal Script zero-initialized?