Unable to acces lists cross site collection using Linq To SharePoint

Question

I'm currently developing a 2010 webpart project, where I query 3 lists on 3 different site collections.

I query these list from a webpart that is located on the root site collection: http://portaltest

Site col 1: http://portaldev/sites/site1 - list x
Site col 2: http://portaldev/sites/site2 - list y
Site col 3: http://portaldev/sites/site2 - list z

When I try to access list x on the site collection: http://portaldev/sites/site1 (from a webpart on the root site collection http://portaldev)
I receive an ArgumentException: {"Web at http://portaldev/sites/site1 could not be found"}

The code that I am using is the folowing

 using (LinqDataContext ctx = new LinqDataContext("http://portaldev/sites/site1"))
 {
     EntityList<listx> entities = ctx.GetList<listx>("listx");
 }

But when I try to run the same webpart on a web of http://portaldev/sites/site1, the code will run an I'm able to query the list x.

Answer 1

Permissions?

Answer 2

Nop,

The account that I am using is over the 3 site collections, site collection admin.

Answer 3

We even tested the code using a console application. In a console application there no problem, but when we use it in a webpart it throws the error.

Answer 4

Does anyone else has the same problem ?

The code works perfectly on a console application one the Sharepoint server but doesn't work in a webpart.

Regards,
Pascal

Answer 5

We have found the cause of this problem. When an SPContext is available (like in the webpart), the constructor of SPServerDataConnection tries the open the url in the SPSite of the context.

So querying a linq datasource in a different site collection doesn't work whenever an SPContext object is available.

We managed to reproduce this problem in our console application by createing a fake SPContext object which causes the same error.

Microsoft.Sharepoint.Linq.Provider - SPServerDataConnection:

public SPServerDataConnection(string url)
{
    if (SPContext.Current != null)
    {
        this.defaultSite = SPContext.Current.Site;
        this.defaultWeb = (SPContext.Current.Web.Url == url) ? SPContext.Current.Web : this.defaultSite.OpenWeb(new Uri(url).PathAndQuery);
    }
    else
    {
        this.defaultSite = new SPSite(url);
        this.defaultWeb = this.defaultSite.OpenWeb(new Uri(url).PathAndQuery);
    }
    if (!this.defaultWeb.Exists)
    {
        throw new ArgumentException(Resources.GetString("CannotFindWeb", new object[] { url }));
    }
    this.defaultWebUrl = this.defaultWeb.ServerRelativeUrl;
    this.openedWebs = new Dictionary<string, SPWeb>();
    this.openedWebs.Add(this.defaultWebUrl, this.defaultWeb);
}

Is there anyone from Microsoft that can confirm if this behaviour is by design or a bug.

Regards,
Pascal

Answer 6

We have found a workaround by changing the SPContext before executing the LINQ query.

In the webpart itself the HttpContext is stored in a variable before executing our search method.

SPSecurity.RunWithElevatedPrivileges(delegate()
{
     using (SPSite contextSite = new SPSite("http://<URL>"))
     {
          using (SPWeb contextWeb = contextSite.OpenWeb())
          {
               HttpRequest httpRequest = new HttpRequest("", contextWeb.Url, "");
               HttpContext.Current = new HttpContext(httpRequest, new HttpResponse(new StringWriter()));
               SPControl.SetContextWeb(HttpContext.Current, contextWeb);               
               using (MyLinqDataContext dc = new MyLinqDataContext("http://<URL>"))
               {
                    EntityList<MyEntity> entities = dc.GetList<MyEntity>("<ListName>");
                    {
                    }
               }
           }
     }
}

After performing the search we set the HttpContext back to the original HttpContext.

tempContext = HttpContext.Current;
this.Search();
HttpContext.Current = tempContext;

I'm not sure if this workaround is appropriate, but at least we can now perform our cross site collection LINQ query in our webpart :)

Regards,
Pascal

Answer 7

Easy solution:

 

http://blog.lekman.com/2010/08/using-linq-to-sharepoint-between-site.html

Thanks to Tobias

Answer 8

Thanks Pascal,  it works for me :)

---

regards, Sudhir Kesharwani

Answer 9

Thanks Pascal ...... it really helped.. 

---

Kunal Valecha

Answer 10

Just use the  constructore of context  and every thing will work fine.

 using (LinqDataContext context = new LinqDataContext('WebPath'))
 {
 
 }

i tried this many times before.

Answer 11

Thanks Pascal, this helped me a lot