I received the following error: "No DataAccessAdapter instance set on LLBLGenProProvider2 instance. Can't execute query"

 protected void PopulateTeamLeaders()
    {
        var q = from c in MetaSingletons.MetaData.VwProjectCollection select c.TeamLeaderName;
        foreach (var leader in q)
        {
            RadTreeNode leaderNode = new RadTreeNode(leader.ToString());
            treProjects.Nodes.Add(leaderNode);

        }
    
        
        using (DataAccessAdapter adapter = clsDatabaseMethods.GetNewAdapter())
        {
        
            ((LLBLGenProProvider2)((IQueryable)q).Provider).AdapterToUse = adapter;

        }
    }

My guess is this: at this part...

foreach (var leader in q)
{
        ...
}

... you are enumerating the query, so that makes the query (q) gets executed. So you are executing the query before setting a valid DataAccessAdapter instance to it. So your code should look like:

protected void PopulateTeamLeaders()
    {
        var q = from c in MetaSingletons.MetaData.VwProjectCollection select c.TeamLeaderName;
        using (DataAccessAdapter adapter = clsDatabaseMethods.GetNewAdapter())
        {       
            ((LLBLGenProProvider2)((IQueryable)q).Provider).AdapterToUse = adapter;
        }

        foreach (var leader in q)
        {
            RadTreeNode leaderNode = new RadTreeNode(leader.ToString());
            treProjects.Nodes.Add(leaderNode);
        }   
    }

I used the following, since your code will show an exception." DataAdapter is been disposed"

protected void PopulateTeamLeaders() { var q = from c in MetaSingletons.MetaData.VwProjectCollection select (c.TeamLeaderName);

    using (DataAccessAdapter adapter = clsDatabaseMethods.GetNewAdapter())
    {
        ((LLBLGenProProvider2)((IQueryable)q).Provider).AdapterToUse = adapter;

        foreach (var leader in q)
        {

            RadTreeNode leaderNode = new RadTreeNode(leader.ToString());
            treProjects.Nodes.Add(leaderNode);


        }
    }


}

weezer wrote:

I received the following error: "No DataAccessAdapter instance set on LLBLGenProProvider2 instance. Can't execute query"

 protected void PopulateTeamLeaders()
    {
        var q = from c in MetaSingletons.MetaData.VwProjectCollection select c.TeamLeaderName;
        foreach (var leader in q)
        {
            RadTreeNode leaderNode = new RadTreeNode(leader.ToString());
            treProjects.Nodes.Add(leaderNode);

        }
    
        
        using (DataAccessAdapter adapter = clsDatabaseMethods.GetNewAdapter())
        {
        
            ((LLBLGenProProvider2)((IQueryable)q).Provider).AdapterToUse = adapter;

        }
    }

Of course this gives this exception. You wrapped the adapter creation with a using statement. While you assign the adapter to the queryable, when the using block exists (the line below the assignment) it will call Dispose on the object in the using(..) statement, which in your case is the adapter object. So you have to execute the query INSIDE the using block.