Graphic tool - Draw Polygon Polygon disappears after finish drawing

[YingLin]

I am using arcGIS silverlight api 2.1 SDK. Created a button for drawing polygon using ESRI:RedlineAction

<esri:RedlineAction
    Color="Red"
    DrawMode="Polygon"                                   
    GraphicsLayerID="MyGraphicsLayer"
    TargetName="Map" />

when drawing is finished, the polygon disappears. I want it to stay so that it can be used when creating printouts. Drawing with polyline and freehand functions are fine though.  Anyone has the same problem?
Thanks very much

[JenniferNery]

If you are using this SDK sample: http://help.arcgis.com/en/webapi/silverlight/samples/start.htm#GraphicsActions

                                <i:Interaction.Triggers>
                                    <i:EventTrigger EventName="Click">
                                        <esri:RedlineAction 
                                    Color="#FF32FF00"
                                    DrawMode="Polygon"                                    
                              GraphicsLayerID="MyGraphicsLayer"
                                    TargetName="MyMap"/>
                                    </i:EventTrigger>
                                </i:Interaction.Triggers>

Notice that the GraphicsLayer it uses is:

            <esri:GraphicsLayer ID="MyGraphicsLayer" Renderer="{StaticResource GraphicsLayerLineSymbol}" />

This Renderer is for Polyline geometry. The graphic is not removed, it is just not rendered because its geometry type cannot be given line symbol. You need to use a different Renderer with symbols that match the geometry type for graphics drawn by RedlineAction.

[YingLin]

Does that mean another graphics Layer have to be created for polygon rendering? The previous api example was able to accommadate both polyline and polygon on same graphic layer.
thanks

[dotMorten_esri]

If you use one of the built-in renderers, the symbol type much match the geometry type, and thus all geometry types must be the same in the layer.

If you don't use a renderer, you can simply assign a symbol directly to each graphic that matches for the geometry type.