void textArea_MouseLeftButtonDown(object sender, MouseButtonEventArgs e) { mode = SelectionMode.None; if (!e.Handled && e.ChangedButton == MouseButton.Left) { ModifierKeys modifiers = Keyboard.Modifiers; bool shift = (modifiers & ModifierKeys.Shift) == ModifierKeys.Shift; if (enableTextDragDrop && e.ClickCount == 1 && !shift) { int visualColumn; int offset = GetOffsetFromMousePosition(e, out visualColumn); if (textArea.Selection.Contains(offset)) { if (textArea.CaptureMouse()) { mode = SelectionMode.PossibleDragStart; possibleDragStartMousePos = e.GetPosition(textArea); } e.Handled = true; return; } } var oldPosition = textArea.Caret.Position; SetCaretOffsetToMousePosition(e); if (!shift) { textArea.ClearSelection(); } if (textArea.CaptureMouse()) { if ((modifiers & ModifierKeys.Alt) == ModifierKeys.Alt && textArea.Options.EnableRectangularSelection) { mode = SelectionMode.Rectangular; if (shift && textArea.Selection is RectangleSelection) { textArea.Selection = textArea.Selection.StartSelectionOrSetEndpoint(oldPosition, textArea.Caret.Position); } } else if (e.ClickCount == 1 && ((modifiers & ModifierKeys.Control) == 0)) { mode = SelectionMode.Normal; if (shift && !(textArea.Selection is RectangleSelection)) { textArea.Selection = textArea.Selection.StartSelectionOrSetEndpoint(oldPosition, textArea.Caret.Position); } } else { SimpleSegment startWord; if (e.ClickCount == 3) { mode = SelectionMode.WholeLine; startWord = GetLineAtMousePosition(e); } else { mode = SelectionMode.WholeWord; startWord = GetWordAtMousePosition(e); } if (startWord == SimpleSegment.Invalid) { mode = SelectionMode.None; textArea.ReleaseMouseCapture(); return; } if (shift && !textArea.Selection.IsEmpty) { if (startWord.Offset < textArea.Selection.SurroundingSegment.Offset) { textArea.Selection = textArea.Selection.SetEndpoint(new TextViewPosition(textArea.Document.GetLocation(startWord.Offset))); } else if (startWord.EndOffset > textArea.Selection.SurroundingSegment.EndOffset) { textArea.Selection = textArea.Selection.SetEndpoint(new TextViewPosition(textArea.Document.GetLocation(startWord.EndOffset))); } this.startWord = new AnchorSegment(textArea.Document, textArea.Selection.SurroundingSegment); } else { textArea.Selection = Selection.Create(textArea, startWord.Offset, startWord.EndOffset); this.startWord = new AnchorSegment(textArea.Document, startWord.Offset, startWord.Length); } } } } e.Handled = true; }