ArcGIS tiled Layer

[YassineEL_JADIDI]

Hi,
I create a map cache service and it work, but the problem is when i try to add a tiled map layer....its not displayed
This is a part of my code, and see if you i have an error plz:

<esri:Map x:Name="MyMap" WrapAround="True" Extent="-1200000,2300000,-1500000,4500000">
           
            <esri:ArcGISTiledMapServiceLayer ID="StreetMapLayer"
                      Url="http://services.arcgisonline.com/ArcGIS/rest/services/World_Imagery/MapServer"/>
               
                <esri:GraphicsLayer ID="MyGraphicsLayer" />
            <esri:GroupLayer ID="Légende">
               
                <esri:GroupLayer ID="Réseau routier">
                    <esri:ArcGISTiledMapServiceLayer ID="Routes Nationales"
                      Url="http://servsig/ArcGIS/rest/services/map/MapServer/15"/>
                    <esri:ArcGISTiledMapServiceLayer ID="Routes Régionales"
                      Url="http://servsig/ArcGIS/rest/services/map/MapServer/16"/>
                    <esri:ArcGISTiledMapServiceLayer ID="Routes Provinciales"
                      Url="http://servsig/ArcGIS/rest/services/map/MapServer/17"/>
                   
                </esri:GroupLayer>
</esri:Map>

[DominiqueBroux]

Since a tiled layer can't be projected on the fly, you can't mix tiled layers with different spatial references in the same map.

The WorlImagery service is in web mercator coordinates and I guess your others tiled layers are not using this spatial reference (probably Lambert from the extent you set).