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Returns the IRange object that represents the cell that lies under the upper-left corner of the specified object.
Use this property to identify the worksheet cell beneath the shape's upper-left corner.
IRange TopLeftCell { get; }
ReadOnly Property TopLeftCell As IRange
IShape shape = worksheet.Shapes.AddShape(AutoShapeType.Rectangle, 20, 20, 120, 60);
IRange range = shape.TopLeftCell;
string address = range.Address;