Arcgis api For silverlight 加载QQ地图

public class QQMapLayer : TiledMapServiceLayer
{
private const double cornerCoordinate = 20037508.342787;
public override void Initialize()
{

this.FullExtent = new ESRI.ArcGIS.Client.Geometry.Envelope(-20037508.342787, -20037508.342787, 20037508.342787, 20037508.342787)
{
SpatialReference = new SpatialReference(102113)
};
// This layer's spatial reference
this.SpatialReference = new SpatialReference(102113);
// Set up tile information. Each tile is 256x256px, 19 levels.
this.TileInfo = new TileInfo()
{
Height = 256,
Width = 256,
Origin = new MapPoint(-cornerCoordinate, cornerCoordinate) { SpatialReference = new ESRI.ArcGIS.Client.Geometry.SpatialReference(102113) },
Lods = new Lod[20]
};
// Set the resolutions for each level. Each level is half the resolution of the previous one.
double[] resolution = new double[]
{
156543.033928,
78271.5169639999,
39135.7584820001,
19567.8792409999,
9783.93962049996,
4891.96981024998,
2445.98490512499,
1222.99245256249,
611.49622628138,
305.748113140558,
152.874056570411,
76.4370282850732,
38.2185141425366,
19.1092570712683,
9.55462853563415,
4.77731426794937,
2.38865713397468,
1.19432856685505,
0.597164283559817,
0.298582141647617
};//cornerCoordinate * 2 / 256;//
for (int i = 0; i < TileInfo.Lods.Length; i++)
{
//TileInfo.Lods[i] = new Lod() { Resolution = Math.Pow(2, 18 - i) };
TileInfo.Lods[i] = new Lod() { Resolution = resolution[i] };

}

// Call base initialize to raise the initialization event
base.Initialize();
}
private string[] _subDomains = new string[] { "p0", "p1", "p2", "p3" };
private int[] scope = new int[] { 0, 0, 0, 0, 0, 3, 0, 3, 0, 3, 0, 3, 0, 7, 0, 7, 0, 15, 0, 15, 0, 31, 0, 31, 0, 63, 4, 59, 0, 127, 12, 115, 0, 225, 28, 227, 356, 455, 150, 259, 720, 899, 320, 469, 1440, 1799, 650, 929, 2880, 3589, 1200, 2069, 5760, 7179, 2550, 3709, 11520, 14349, 5100, 7999, 23060, 28689, 10710, 15429, 46120, 57369, 20290, 29849, 89990, 124729, 41430, 60689, 184228, 229827, 84169, 128886 };
public override string GetTileUrl(int level, int row, int col)
{
var subdomain = this._subDomains[(level + col + row) % this._subDomains.Length];

string baseUrl = "http://{0}.map.qq.com/maptiles/{1}";
//
var f = level * 4;
if (f == this.scope.Length) return "";
var i = this.scope[f++];

var j = this.scope[f++];

var l = this.scope[f++];

var scope = this.scope[f];

var tileNo = "";

if (col >= i && col <= j && row >= l && row <= scope)
{

row = (int)(Math.Pow(2, level) - 1 - row);

tileNo = level + "/" + Math.Floor(col / 16) + "/" + Math.Floor(row / 16) + "/" + col + "_" + row + ".png";

}

return string.Format(baseUrl, subdomain, tileNo);
}
}