Text Editing and Sources

TTMSFNCMemo exposes the full set of text-manipulation operations you would expect from a code editor, plus a multi-source model for switching between open files without losing per-file state.

Loading and saving text

Set Text or Lines directly, or load from file or URL:

TMSFNCMemo1.LoadFromFile('C:\Projects\unit1.pas');
TMSFNCMemo1.LoadFromURL('https://example.com/main.js');
// Save: write Text to a TStringList or file yourself
TFile.WriteAllText('out.pas', TMSFNCMemo1.Text);

LoadFromFile automatically selects the language by matching the file extension against LanguageFileExtensionsMap.

Clipboard, selection, undo/redo

// --- Text content ---
TMSFNCMemo1.Text := 'begin' + sLineBreak + '  WriteLn(''Hello'');' + sLineBreak + 'end.';
TMSFNCMemo1.Lines.Add('// added line');

// Load and save
TMSFNCMemo1.LoadFromFile('C:\Projects\code.pas');
// (save is handled by writing TMSFNCMemo1.Text to a file)

// --- Clipboard ---
TMSFNCMemo1.CopyToClipBoard;
TMSFNCMemo1.PasteFromClipBoard;
TMSFNCMemo1.CutToClipBoard;
TMSFNCMemo1.SelectAll;
TMSFNCMemo1.Unselect;
TMSFNCMemo1.Undo;
TMSFNCMemo1.Redo;
TMSFNCMemo1.FormatDocument;

// --- Selection ---
TMSFNCMemo1.SelStart  := 0;
TMSFNCMemo1.SelLength := 10;
ShowMessage(TMSFNCMemo1.SelText);
TMSFNCMemo1.DeleteSelection;

// --- Multi-source editing ---
// Add sources programmatically
TMSFNCMemo1.Sources.AddSource('program Project1;', mlPascal, 'project1.dpr');
TMSFNCMemo1.Sources.AddSource('{"key": "value"}', mlJson, 'config.json');
TMSFNCMemo1.Sources.AddSourceFromFile('C:\Projects\unit1.pas');

// Switch between sources (0-based index)
TMSFNCMemo1.ActiveSource := 1;

// Add all files in a folder
TMSFNCMemo1.AddSourcesFromFolder('C:\Projects\src\');

// --- File extension → language mapping ---
// Add a custom extension for an existing language
with TMSFNCMemo1.LanguageFileExtensionsMap.Add do
begin
  Language  := mlCpp;
  Extension := '.cu';   // CUDA source files
end;

// --- Drag and drop (FMX) ---
procedure TForm1.TMSFNCMemo1DragDrop(Sender: TObject; const Data: TDragObject;
  const Point: TPointF);
var
  obj: TTMSFNCMemoDragObject;
begin
  obj := Data.Source as TTMSFNCMemoDragObject;
  if obj.Kind = otText then
    TMSFNCMemo1.Lines.Add(obj.Text)
  else if obj.Files.Count > 0 then
    obj.Files[0].Open;
end;

TTMSFNCMemo with Pascal syntax highlighting

Sources — editing multiple files

Sources is an ordered collection of TTMSFNCMemoSource items. Each source retains its own Language, Text, CaretPosition, breakpoints, bookmarks, and line highlights when you switch away from it.

// Add sources
TMSFNCMemo1.Sources.AddSource('',   mlPascal, 'Unit1.pas');
TMSFNCMemo1.Sources.AddSource('{}', mlJson,   'config.json');
TMSFNCMemo1.Sources.AddSourceFromFile('C:\Projects\module.ts');
TMSFNCMemo1.AddSourcesFromFolder('C:\Projects\src\');

// Switch the active source (0-based index)
TMSFNCMemo1.ActiveSource := 1;

TTMSFNCMemoSource also exposes its own SaveToFile for writing individual files back:

TMSFNCMemo1.Sources[0].SaveToFile('C:\Projects\unit1.pas');

File extension to language mapping

TTMSFNCMemo ships with built-in extension mappings (e.g. .pas → Pascal, .ts → TypeScript). Register additional extensions through LanguageFileExtensionsMap:

with TMSFNCMemo1.LanguageFileExtensionsMap.Add do
begin
  Language  := mlCpp;
  Extension := '.cu';   // CUDA source files
end;
// Convenience overload
TMSFNCMemo1.LanguageFileExtensionsMap.Add(mlPascal, '.dpr');

Drag and drop

TTMSFNCMemo supports dragging text and files directly into the editor. Because the editor runs inside a TTMSFNCWebBrowser, file access has some constraints: the filename is only available in the DragDrop event; in all preceding events (DragOver, DragEnter) only the MIME type is available.

Handle OnDragDrop to decide what to do with dropped content:

procedure TForm1.TMSFNCMemo1DragDrop(Sender: TObject; const Data: TDragObject;
  const Point: TPointF);
var
  obj: TTMSFNCMemoDragObject;
begin
  obj := Data.Source as TTMSFNCMemoDragObject;
  if obj.Kind = otText then
    TMSFNCMemo1.Lines.Add(obj.Text)
  else if obj.Files.Count > 0 then
    obj.Files[0].Open;
end;

In VCL, set Allow := False in DragOver to prevent the drop; in FMX, set Operation := TDragOperation.None.

Note

Setting Allow / Operation to prevent a drop does not update the cursor visual in the editor, because cursor rendering is controlled by the embedded browser.

Combining sources, file extension mapping, and drag-and-drop

procedure TForm1.FormCreate(Sender: TObject);
begin
  TMSFNCMemo1.LanguageFileExtensionsMap.Add(mlPascal, '.dpr');
  TMSFNCMemo1.AddSourcesFromFolder('C:\Projects\src\');
  TMSFNCMemo1.ActiveSource := 0;
end;

procedure TForm1.TMSFNCMemo1DragDrop(Sender: TObject;
  const Data: TDragObject; const Point: TPointF);
var
  obj: TTMSFNCMemoDragObject;
begin
  obj := Data.Source as TTMSFNCMemoDragObject;
  if (obj.Kind = otFile) and (obj.Files.Count > 0) then
    obj.Files[0].Open;
end;

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