Inno Setup - 卸载时不显示进度条

Question

I'm using Inno Setup to create my own installer. When user uninstall app I want delete some folder.

So I use CurUninstallStepChanged event to delete folder and show "progress bar" with npbstMarquee style (based on Inno Setup: How to handle progress bar on [UninstallDelete] section? ).

Here is the code:

procedure DeleteFolder();
var
  FindRec: TFindRec;
  fullPath: string;
  tmpMsg: string;
  StatusText: string;
  deletePath: string;
begin
  { find all and delete }
  UninstallProgressForm.ProgressBar.Style := npbstMarquee;       
  StatusText := UninstallProgressForm.StatusLabel.Caption;
  UninstallProgressForm.StatusLabel.WordWrap := True;
  UninstallProgressForm.StatusLabel.AutoSize := True;
  fullPath := 'C:\ProgramData\TestPath';
  if FindFirst(ExpandConstant(fullPath + '\*'), FindRec) then 
  try
    repeat
      if (FindRec.Attributes and FILE_ATTRIBUTE_DIRECTORY <> 0) and 
         (FindRec.Name <> '.') and (FindRec.Name <> '..') then begin
            deletePath := AddBackslash(fullPath) + FindRec.Name;
            tmpMsg := 'Deleting...' + #13#10 + deletePath;
            UninstallProgressForm.StatusLabel.Caption := tmpMsg;
            DelTree(deletePath, True, True, True);
        end;
    until
      not FindNext(FindRec);
  finally
    UninstallProgressForm.StatusLabel.Caption := StatusText;
    FindClose(FindRec);
  end;
  UninstallProgressForm.ProgressBar.Style := npbstNormal;
end;

{ Uninstall event }
procedure CurUninstallStepChanged(CurUninstallStep: TUninstallStep);
begin
   case CurUninstallStep of
    usUninstall:
     begin
       DeleteFolder();
    end;
  end;
end;

If I using debug each line, I can see progress bar running. But when I using unins000.exe then only Caption can show, progress bar is not showing.
How can I fix it?

Answer 1

You have to pump the message queue to display/animate the progress bar.
Inno Setup: How to modify long running script so it will not freeze GUI?

Particularly, you can use the AppProcessMessage function from:
My SQL server discovery on LAN by listening port (Inno Setup)

Though with use of DelTree , the interval between calls to AppProcessMessage will be too big to animate the progress bar smoothly. You would have to implement a recursive delete explicitly to allow pumping the queue frequently enough.