User Management through Win32 call

Check out the JCL (JediVCL) it has a routine from lanmanager(JcLanMan.pas)

function CreateAccount(const Server, Username, Fullname, Password,
Description,
  Homedir, Script: string; const PasswordNeverExpires: Boolean):
Boolean;
var
  wServer, wUsername, wFullname,
  wPassword, wDescription, wHomedir, wScript: WideString;
  Details: USER_INFO_2;
  Err: NET_API_STATUS;
  ParmErr: DWORD;
begin
  wServer := Server;
  wUsername := Username;
  wFullname := Fullname;
  wPassword := Password;
  wDescription := Description;
  wScript := Script;
  wHomedir := Homedir;

  FillChar (Details, SizeOf(Details), 0);
  with Details do
  begin
    usri2_name := PWideChar(wUsername);
    usri2_full_name := PWideChar(wFullname);
    usri2_password := PWideChar(wPassword);
    usri2_comment := PWideChar(wDescription);
    usri2_priv := USER_PRIV_USER;
    usri2_flags := UF_SCRIPT;
    if PassWordNeverExpires then
      usri2_flags := usri2_flags or UF_DONT_EXPIRE_PASSWD;
    usri2_script_path := PWideChar(wScript);
    usri2_home_dir := PWideChar(wHomedir);
    usri2_acct_expires := TIMEQ_FOREVER;
  end;

  Err := NetUserAdd(PWideChar(wServer), 2, @Details, @ParmErr);
  Result := (Err = NERR_SUCCESS);
end;

C:\>cacls /?
Displays or modifies access control lists (ACLs) of files

CACLS filename [/T] [/E] [/C] [/G user:perm] [/R user [...]]
[/P user:perm [...]] [/D user [...]]
filename Displays ACLs.
/T Changes ACLs of specified files in
the current directory and all subdirectories.
/E Edit ACL instead of replacing it.
/C Continue on access denied errors.
/G user:perm Grant specified user access rights.
Perm can be: R Read
C Change (write)
F Full control
/R user Revoke specified user's access rights (only valid with /E).
/P user:perm Replace specified user's access rights.
Perm can be: N None
R Read
C Change (write)
F Full control
/D user Deny specified user access.
Wildcards can be used to specify more that one file in a command.
You can specify more than one user in a command.

Add checkboxes to a TShellTreeView

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, ShellCtrls;

type
TCheckBoxShellTreeView = class(ShellCtrls.TShellTreeView)
public
procedure CreateParams(var Params: TCreateParams); override;
end;

TForm1 = class(TForm)
procedure FormCreate(Sender: TObject);
private
{ Private declarations }
ShellTreeView: TCheckBoxShellTreeView;
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

const
TVS_CHECKBOXES = $00000100;

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
ShellTreeView := TCheckBoxShellTreeView.Create(Self);
with ShellTreeView do
begin
Name := 'ShellTreeView';
Parent := Self;
Root := 'rfDesktop';
UseShellImages := True;
Align := alClient;
AutoRefresh := False;
BorderStyle := bsNone;
Indent := 19;
ParentColor := False;
RightClickSelect := True;
ShowRoot := False;
TabOrder := 0;
end;
end;

procedure TCheckBoxShellTreeView.CreateParams(var Params: TCreateParams);
begin
inherited;
Params.Style := Params.Style or TVS_CHECKBOXES;
end;

end.

Adding TCheckbox to TCombobox

You need to do the following:

Set ComboBox.Style:=csOwnerDrawFixed

//..... your form class
private
Selected: array of Boolean;
//.....

procedure TForm1.ComboBox1DrawItem(Control: TWinControl;
     Index: Integer; Rect: TRect; State: TOwnerDrawState);
begin
  SetLength(Selected, TComboBox(Control).Items.Count);
  with TComboBox(Control).Canvas do
  begin
    FillRect(rect);

    Rect.Left := Rect.Left + 1;
    Rect.Right := Rect.Left + 13;
    Rect.Bottom := Rect.Bottom;
    Rect.Top := Rect.Top;

    if not (odSelected in State) and (Selected[Index]) then
      DrawFrameControl(Handle, Rect, DFC_BUTTON,
        DFCS_BUTTONCHECK or DFCS_CHECKED or DFCS_FLAT)
    else if (odFocused in State) and (Selected[Index]) then
      DrawFrameControl(Handle, Rect, DFC_BUTTON,
        DFCS_BUTTONCHECK or DFCS_CHECKED or DFCS_FLAT)
    else if (Selected[Index]) then
      DrawFrameControl(Handle, Rect, DFC_BUTTON,
        DFCS_BUTTONCHECK or DFCS_CHECKED or DFCS_FLAT)
    else if not (Selected[Index]) then
      DrawFrameControl(Handle, Rect, DFC_BUTTON, DFCS_BUTTONCHECK or DFCS_FLAT);

    TextOut(Rect.Left + 15, Rect.Top, TComboBox(Control).Items[Index]);
  end;
end;

procedure TForm1.ComboBox1Select(Sender: TObject);
var
  i: Integer;
  Sel: string;
begin
  Sel := EmptyStr;
  Selected[TComboBox(Sender).ItemIndex] := not Selected[TComboBox(Sender).ItemIndex];
  for i := 0 to TComboBox(Sender).Items.Count - 1 do
    if Selected[i] then
      Sel := Sel + TComboBox(Sender).Items[i] + ' ';
  ShowMessage(Sel);  //Just for test...
end;