Necesito dibujar un rectángulo con un símbolo de relleno simple

Question

Necesito dibujar este rectángulo en layoutview :

Intento esto pero no funciona. ¿Cómo puedo dibujar este rectángulo?

        IPoint p1 = new PointClass();

        p1.X = 9.9936; p1.Y = 5.8777;

        IPoint p2 = new PointClass();

        p2.X = p1.X; p2.Y = p1.Y + 2.62;

        IPoint p3 = new PointClass();

        p3.X = p1.X + 0.152 ; p3.Y = p1.Y;

        IPoint p4 = new PointClass();

        p4.X = p3.X; p4.Y = p3.Y + 2.62;

        IPointCollection ring = new RingClass();
        ring.AddPoint(p1);
        ring.AddPoint(p2);
        ring.AddPoint(p3);
        ring.AddPoint(p4);

        IRgbColor color = new RgbColorClass();
        color.Red = 255; color.Blue = 28; color.Green = 20;

        ISimpleFillSymbol simpleFillSymbol = new SimpleFillSymbolClass();
        simpleFillSymbol.Color = color;

        IElement element = new PolygonElement();
        element.Geometry = ring as IGeometry;  // I try this.
        element. ???  // I need to apply symbol on this element. but it hasn't symbol property

        IMxDocument mxdoc = ArcMap.Application.Document as IMxDocument;
        IPageLayout pageLayout = new PageLayout();
        pageLayout = mxdoc.PageLayout;
        IGraphicsContainer graphicsContainer = pageLayout as IGraphicsContainer;
        graphicsContainer.AddElement(element, 0);

        IActiveView activeView = pageLayout as IActiveView;

        activeView.Refresh();

Esta solución tiene problemas en :

    IElement element = new PolygonElement();
    element.Geometry = ring as IGeometry;  
    ((IFillShapeElement)element).Symbol = (IFillSymbol)simpleFillSymbol;

La solución de @Berend está funcionando..

Answer 1

Personalmente preferiría una versión más corta:

private void AddRectangle()
{
    var element = new RectangleElementClass
    {
        Geometry = new EnvelopeClass {XMin = 9.9936, YMin = 5.8777, Width = 0.152, Height = 2.62},
        Symbol = new SimpleFillSymbolClass {Color = new RgbColorClass {Red = 255, Green = 20, Blue = 28}}
    };

    var mxdoc = ArcMap.Application.Document as IMxDocument;
    var graphicsContainer = mxdoc.PageLayout as IGraphicsContainer;
    graphicsContainer.AddElement(element, 0);

    (mxdoc.PageLayout as IActiveView).PartialRefresh(esriViewDrawPhase.esriViewGraphics, element, null);
}

Answer 2

Pruebe

((IFillShapeElement)element).Symbol = (IFillSymbol)simpleFillSymbol;