arcgis for silverlight调天地图服务不显示地图

我用按照网上调用天地图的方法写了一段代码但是就是不显示地图。
客户给的天地图服务只有3级从18级开始，而网上的一般都是从0级开始不知道是不是这方面我的有问题。
下面是我的代码

this.FullExtent = new
        ESRI.ArcGIS.Client.Geometry.Envelope(118.229752145124, 36.0666713776665, 118.826389346455, 36.6236108423721);
        {
            SpatialReference = new ESRI.ArcGIS.Client.Geometry.SpatialReference(4326);
        };
        this.SpatialReference = new ESRI.ArcGIS.Client.Geometry.SpatialReference(4326);
        this.TileInfo = new TileInfo()
        {
            Height = 256,
            Width = 256,
            Origin = new ESRI.ArcGIS.Client.Geometry.MapPoint(118.229752145124, 36.6236108423721)
            {
                SpatialReference = new ESRI.ArcGIS.Client.Geometry.SpatialReference(4326)
            },
            Lods = new Lod[3]
        };
                TileInfo.Lods[0] = new Lod() { Resolution = 0.0000026822090148926 };
        TileInfo.Lods[1] = new Lod() { Resolution = 0.0000013411045074463 };
        TileInfo.Lods[2] = new Lod() { Resolution = 0.0000006705522537232 };

        base.Initialize();

                public override string GetTileUrl(int level, int row, int col)
    {
        string url = "http://lqmap.linqu.gov.cn//newmap/tianditu/linqu/verctor/wmts?SERVICE=WMTS&REQUEST=GetTile&VERSION=1.0.0&LAYER=verctor&STYLE=default&TILEMATRIXSET=Matrix_0&TILEMATRIX=" + level.ToString() + "&TileRow=" + row.ToString() + "&TileCol=" + col.ToString() + "&FORMAT=image/png";
        return url;

    }

请高手帮我看看

博主,我也遇到同样的问题,地图显示不出来,也只有3-18级, 你是怎么解决的,给点思路或代码