How to get the current process list in windows

Question

I'm trying to show all processes which are currently running on my system. Can any one guide me to do that.

Answer 1

I would use WMI for this task since WMI can list also 64-bit processes which I think the Windows API way cannot. Here is an example which uses the Win32_Process class to query list of running processes:

[Setup]
AppName=My Program
AppVersion=1.5
DefaultDirName={pf}\My Program

[Code]
const
  WM_SETREDRAW = $000B;
var
  ProcessList: TNewListBox;

// this is a substitution for missing BeginUpdate method
// of TStrings class
procedure WinControlBeginUpdate(Control: TWinControl);
begin
  SendMessage(Control.Handle, WM_SETREDRAW, 0, 0);
end;

// this is a substitution for missing EndUpdate method
// of TStrings class
procedure WinControlEndUpdate(Control: TWinControl);
begin
  SendMessage(Control.Handle, WM_SETREDRAW, 1, 0);
  Control.Refresh;
end;

function GetProcessNames(Items: TStrings): Integer;
var
  I: Integer;
  WQLQuery: string;
  WbemLocator: Variant;
  WbemServices: Variant;
  WbemObject: Variant;
  WbemObjectSet: Variant;
begin
  Result := 0;

  WbemLocator := CreateOleObject('WbemScripting.SWbemLocator');
  WbemServices := WbemLocator.ConnectServer('localhost', 'root\CIMV2');

  WQLQuery := 'SELECT Name FROM Win32_Process';

  WbemObjectSet := WbemServices.ExecQuery(WQLQuery);
  if not VarIsNull(WbemObjectSet) and (WbemObjectSet.Count > 0) then
  begin
    Items.Clear;
    for I := 0 to WbemObjectSet.Count - 1 do
    begin
      WbemObject := WbemObjectSet.ItemIndex(I);
      if not VarIsNull(WbemObject) then
        Items.Add(WbemObject.Name);
    end;
    Result := Items.Count;
  end;
end;

procedure RefreshButtonClick(Sender: TObject);
begin
  // this try..finally block is used to reduce annoying visual effects
  // when filling the list box; Inno Setup doesn't publish BeginUpdate,
  // EndUpdate method pair, hence this home brewn solution
  WinControlBeginUpdate(ProcessList);
  try
    GetProcessNames(ProcessList.Items);
  finally
    WinControlEndUpdate(ProcessList);
  end;
end;

procedure InitializeWizard;
var
  RefreshBtn: TNewButton;
  ProcessPage: TWizardPage;
begin
  ProcessPage := CreateCustomPage(wpWelcome, 'Caption', 'Description');

  ProcessList := TNewListBox.Create(WizardForm);
  ProcessList.Parent := ProcessPage.Surface;
  ProcessList.SetBounds(0, 0, ProcessPage.SurfaceWidth,
    ProcessPage.SurfaceHeight - 33);

  RefreshBtn := TNewButton.Create(WizardForm);
  RefreshBtn.Parent := ProcessPage.Surface;
  RefreshBtn.Left := 0;
  RefreshBtn.Top := ProcessPage.SurfaceHeight - RefreshBtn.Height;
  RefreshBtn.Caption := 'Refresh';
  RefreshBtn.OnClick := @RefreshButtonClick;
end;