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Gets or sets the text direction.
Use this property to determine how text is oriented within the shape's text frame, such as horizontal, vertical, rotated, or stacked text.
TextDirection Direction { get; set; }
Property Direction As TextDirection
IShape shape = worksheet.Shapes.AddShape(AutoShapeType.Rectangle, 10, 10, 120, 60);
ITextFrame textFrame = shape.TextFrame;
textFrame.Direction = TextDirection.Vertical;
TextDirection direction = textFrame.Direction;