LinqToEntitiesDomainService Dynamic Binding DataBase ，Silverlight RIA 动态绑定数据库

手上有个搜索引擎的项目，每个行业都有一个独立的数据库，这些数据库schemas都是一样。这样RIA就需要根据客户选择的不同行业连接到不同的数据库。解决办法参看 链接

这个方法不是最理想的，大致代码如下

在silverlight端

private void SetCookie(string cookieName, string cookieValue)
{
  DateTime expireDate = DateTime.Now + TimeSpan.FromDays(1); 
  string newCookie = cookieName + "=" + cookieValue + ";expires=" + expireDate.ToString("R");
  HtmlPage.Document.SetProperty("cookie", newCookie);
}

在RIA端override 
protected override ProjectEntities CreateObjectContext()
{
  long projectId = -1;
  StringBuilder connection;
  if (System.Web.HttpContext.Current.Request.Cookies["SelectedProjectId"] != null)
  {
    projectId = Convert.ToInt64(System.Web.HttpContext.Current.Request.Cookies["SelectedProjectId"].Value);
  }
  else throw new Exception("Selected Project ID Exception");  // temporary

  // Verify this user has access to the DB just in case it's spoofed 

  // Lookup project ID in my database to get the database name and server name

  // Load template connection string found in web.config
  // Replace the template holders for SERVER_NAME and DATABASE_NAME with above lookup values

  return new ProjectEntities(MyDynamicConnectionString);      
}