Question

Here is what I am “trying” to achieve

I have a function to generate passwords which I then add into a TStringList after this I should populate the VirtualTreeView with the items but I am having no luck in getting anywhere fast with doing so. How should it be done the correct way? I am still learning and am not a professional.

My function for generating the passwords:

function Generate(AllowUpper,AllowLower,AllowNumbers,AllowSymbols:Boolean; PassLen:Integer):String;
const
  UpperList  = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
  LowerList  = 'abcdefghijklmnopqrstuvwxyz';
  NumberList = '0123456789';
  SymbolList = '!#$%&/()=?@<>|{[]}\*~+#;:.-_';
var
  MyList  : String;
  Index   : Integer;
  i       : Integer;
begin
  Result:='';
  MyList:='';
   //here if the flag is set the elements are added to the main array (string) to process
   if AllowUpper   then MyList := MyList + UpperList;
   if AllowLower   then MyList := MyList + LowerList;
   if AllowNumbers then MyList := MyList + NumberList;
   if AllowSymbols then MyList := MyList + SymbolList;

   Randomize;
   if Length(MyList)>0 then
   for i := 1 to PassLen do
   begin
    Index := Random(Length(MyList))+1;
    Result := Result+MyList[Index];
  end;
end;

Here is how I am calling it

procedure TMain.Button3Click(Sender: TObject);
var
  i: integer;
  StrLst: TStringList;
// Timing vars...
  Freq, StartCount, StopCount: Int64;
  TimingSeconds: real;
begin
  vst1.Clear;
  Panel2.Caption := 'Generating Passwords...';
  Application.ProcessMessages;
// Start Performance Timer...
  QueryPerformanceFrequency(Freq);
  QueryPerformanceCounter(StartCount);

  StrLst := TStringList.Create;
  try
  for i := 1 to PassLenEd.Value do
   StrLst.Add(Generate(ChkGrpCharSelect.Checked[0],ChkGrpCharSelect.Checked[1],
    ChkGrpCharSelect.Checked[2],ChkGrpCharSelect.Checked[3],20));
// Stop Performance Timer...
    QueryPerformanceCounter(StopCount);
    TimingSeconds := (StopCount - StartCount) / Freq;
// Display Timing... How long it took to generate
    Panel2.Caption := 'Generated '+IntToStr(PassLenEd.Value)+' passwords in '+
    FloatToStrF(TimingSeconds,ffnumber,1,3)+' seconds';

// Add to VirtualTreeList - here???
finally
    StrLst.Free;
  end;
end;

I expect that I am doing this completely the wrong way, I have been trying for 2 days now, it would be great if someone could put me straight with how I should go about it.

Chris

Answer 1

Or if you really want VirtualTreeView, you can use something like this …
I’m not sure if this is absolutely clear solution, I’m familiar with records, not only one single variables.

procedure TMain.Button3Click(Sender: TObject);
var i: integer;
    p: PString;
    Freq, StartCount, StopCount: Int64;
    TimingSeconds: real;

begin
  Panel2.Caption := 'Generating Passwords...';
  Application.ProcessMessages;

  QueryPerformanceFrequency(Freq);
  QueryPerformanceCounter(StartCount);

  vst1.BeginUpdate;
  vst1.Clear;

  for i := 1 to PassLenEd.Value do
    begin
      p := VirtualStringTree1.GetNodeData(VirtualStringTree1.AddChild(nil));
      p^ := Generate(ChkGrpCharSelect.Checked[0],ChkGrpCharSelect.Checked[1], ChkGrpCharSelect.Checked[2],ChkGrpCharSelect.Checked[3],20);
    end;

  vst1.EndUpdate;

  QueryPerformanceCounter(StopCount);
  TimingSeconds := (StopCount - StartCount) / Freq;
  Panel2.Caption := 'Generated '+IntToStr(PassLenEd.Value)+' passwords in '+
  FloatToStrF(TimingSeconds,ffnumber,1,3)+' seconds';
end;

And you need to implement OnGetNodeDataSize and OnGetText events to initialize node data size and to display the text.

procedure TMain.vst1GetNodeDataSize(
  Sender: TBaseVirtualTree; var NodeDataSize: Integer);
begin
  NodeDataSize := SizeOf(string);
end;

procedure TMain.vst1GetText(Sender: TBaseVirtualTree;
  Node: PVirtualNode; Column: TColumnIndex; TextType: TVSTTextType;
  var CellText: string);
begin
  CellText := PString(VirtualStringTree1.GetNodeData(Node))^;
end;

Edit 1: I’ve corrected data types UnicodeString -> String