Inno Setup: Marquee style progress bar for lengthy synchronous operation in C# DLL

Question

I create setup for my program using Inno Setup. I have code C# and some wizard page runs it. I want to see "ProgressBar" (style Marquee) when my code C# works a lo

Answer 1

This is not easy. Calling into synchronous function effectively blocks the GUI thread. So you cannot animate the progress bar.

You have to run the lengthy task on a different thread. As it seems to be your DLL, you can modify it to offer an asynchronous API. Something like:

private static Task _task = null;
private static int _outcome;

[DllExport(CallingConvention = CallingConvention.StdCall)]
public static void StartSomething()
{
    // Starts an operation on a different thread
    _task = new Task(() => { Something(); });
    _task.Start();
}

// The operation to run on a different thread
private static void Something()
{
    // The lengthy operation
    Thread.Sleep(10000);
    // Remember the results
    _outcome = 123;
}

[DllExport(CallingConvention = CallingConvention.StdCall)]
public static bool HasSomethingCompleted(out int outcome)
{
    // Check if the operation has completed
    bool result = _task.IsCompleted;
    // And collect its results
    outcome = _outcome;
    return result;
}

And then you can use this from Inno Setup like:

procedure InitializeWizard();
begin
  ServerDetailsPage := CreateInputQueryPage(wpWelcome, '', '', '...');
end;

procedure CallDll;
var
  ProgressPage: TOutputProgressWizardPage;
  Outcome: Integer;
begin
  StartSomething;

  ProgressPage := CreateOutputProgressPage('Calling DLL', '');
  ProgressPage.Show;
  try
    ProgressPage.SetProgress(0, 100);
    ProgressPage.ProgressBar.Style := npbstMarquee;
    { wait for the Something to finish }
    while not HasSomethingCompleted(Outcome) do
    begin
      { And pump windows message queue frequently to animate the progress bar }
      ProgressPage.SetProgress(0, 100);
      Sleep(50);
    end;

  finally
    ProgressPage.Hide;
    ProgressPage.Free;
  end;

  MsgBox(Format(
    'Something has finished and the outcome was %d', [Outcome]), mbInformation, MB_OK);
end;

function NextButtonClick(CurPageID: Integer): Boolean;
begin
  if CurPageID = ServerDetailsPage.ID then
  begin
    CallDll;
  end;
  Result := True;
end;

For a similar question see:
How to delay without freezing in Inno Setup

---

Note that the marquee style progress bar does not work in Inno Setup 6.1. You have to use an older version. See https://groups.google.com/g/innosetup/c/9eisZhaDsJQ.