Telerik Openaccess & Linq compiled expression

1 posts, 0 answers
  1. Matteo Ermidoro
    Matteo Ermidoro avatar
    1 posts
    Member since:
    Aug 2009

    Posted 26 Aug 2009 Link to this post

    Hello, 

    I'm trying to create a "generic" datalayer for my apps. At the moment I'm facing some issue creating a method with this sign :

    public T GetSingle<T>(Expression<Func<T, bool>> filter)

    I want to use Expression<Func<T, bool>> filter to pass "where" statement to my DAL. 

    My code is : 
                var predicate = filter.Compile();
                var scope = ObjectScopeProvider.ObjectScope(ScopeContext.Application);           

                var obj1 = scope.Extent<T>().Where<T>(p => predicate(p));

    but with no luck, last row throw this exeption :
    System.NotSupportedException was unhandled
      Message="RegionExtent.OfType().Where(p => Invoke(value(OfeX.DataLayer.DatabaseServices.DataBaseServices+<>c__DisplayClass0`1[OfEx.PersistentClasses.Region]).predicate,p))"
      Source="Telerik.OpenAccess.Query"
      StackTrace:
           at Telerik.OpenAccess.Query.QueryContext.CreatedQuery(IQueryable x)
           at Telerik.OpenAccess.Query.QueryContext.CreatedQuery[T](IQueryable`1 x)
           at Telerik.OpenAccess.Query.ObjectScopeQuery`2.CreateQuery[TElement](Expression expressionParam)
           at System.Linq.Queryable.Where[TSource](IQueryable`1 source, Expression`1 predicate)
           at OfeX.DataLayer.DatabaseServices.DataBaseServices.GetSingle[T](Expression`1 filter) in C:\Data\Visual Studio 2005\Projects\OfEx\Ofex\Ofex.DataLayer\DatabaseServices\DataBaseServices.cs:line 74
           at TestDataLayer.Form1.button3_Click(Object sender, EventArgs e) in C:\Data\Visual Studio 2005\Projects\OfEx\Ofex\TestDataLayer\Form1.cs:line 56
           at System.Windows.Forms.Control.OnClick(EventArgs e)
           at System.Windows.Forms.Button.OnClick(EventArgs e)
           at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
           at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
           at System.Windows.Forms.Control.WndProc(Message& m)
           at System.Windows.Forms.ButtonBase.WndProc(Message& m)
           at System.Windows.Forms.Button.WndProc(Message& m)
           at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
           at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
           at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
           at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
           at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData)
           at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
           at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
           at System.Windows.Forms.Application.Run(Form mainForm)
           at TestDataLayer.Program.Main() in C:\Data\Visual Studio 2005\Projects\OfEx\Ofex\TestDataLayer\Program.cs:line 18
           at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
           at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
           at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
           at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
           at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
           at System.Threading.ThreadHelper.ThreadStart()
      InnerException: 


    Anyone could help? 

    Thanks a lot.

    Matteo


    -------------------------------------------------------
    Solved : 
    Seems to be a problem with OpenAccess & "var predicate = filter.Compile();".

    I modified the last row in 
    var obj1 = scope.Extent<T>().Where<T>(filter);

    and now it works.

    Thanks 

    Matteo
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