Is there a way to have a textbox auto size to the size of the inserted text?
Thanks for your inquiry. Please use Shape.TextBox.FitShapeToText to determines whether Microsoft Word will grow the shape to fit text.
Document doc = new Document(MyDir + "in.docx");
Shape shape = (Shape)doc.GetChild(NodeType.Shape, 0, true);
shape.TextBox.FitShapeToText = true;
doc.Save(MyDir + "18.4.docx");