private void CreateUrl()
{
#region 构造真正的URL
//http://localhost:7080/output/World_512X512/10000/1/1.png
StringBuilder builder = new StringBuilder();
builder.Append(this.CachedUrl);
builder.AppendFormat("/{0}_{1}x{1}", this.MapName, this.TileSize);
builder.Append("/{0}/{1}/{2}.");
builder.AppendFormat("{0}", ImageFormat);
#endregion
this.uriFormat = builder.ToString();
}