Question

I can’t update when I change some field in my table.

• Database ==> mysql
• .net framework ==> 4.0
• platform==> wpf app

let me explain step by step

my aim is updating item which already exists in table.

   public bool SaveToVideoInfo(List<tblvideoinfo> vList,sbyte profilID)
    {
                     foreach (tblvideoinfo _videoinfo in vList)
            {

                try
                {

                ent.AddTotblvideoinfo(_videoinfo);
                ent.AddTotblprocess(CreateProcess(profilID,_videoinfo.VideoID));
                ent.SaveChanges();

                }
                catch (UpdateException )
                {

                   return UpdateToVideoInfo(_videoinfo);
                }            
        }

            return false;                     
    }

if already item exists in table, I’m catching this exception and calling my update function

    public bool UpdateToVideoInfo(tblvideoinfo vInfo)
    {

        var updatingItem = (from a in ent.tblvideoinfo
                  where a.VideoID == vInfo.VideoID
                  select a).First();

        updatingItem.SearchKeywords = vInfo.SearchKeywords;
        updatingItem.SearchTimeStamp = DateTime.Now;

        return ent.SaveChanges() > 0;

    }

because if it exists in table, I want to change some field as I wrote above. Everything is fine until running ent.SaveChanges()

I checked updatingItem has been changed which I set properties (SearchKeywords ,SearchTimeStamp )

But this error occurs

error occurred while updating the entries. See the inner exception for details

here are details

 at System.Data.Mapping.Update.Internal.UpdateTranslator.Update(IEntityStateManager stateManager, IEntityAdapter adapter)
   at System.Data.EntityClient.EntityAdapter.Update(IEntityStateManager entityCache)
   at System.Data.Objects.ObjectContext.SaveChanges(SaveOptions options)
   at System.Data.Objects.ObjectContext.SaveChanges()
   at MyDbHelper.DBHelper.UpdateToVideoInfo(tblvideoinfo vInfo)
   at MyDbHelper.DBHelper.SaveToVideoInfo(List`1 vList, SByte profilID)
   at youtube.MainWindow.p_Drop_Event(Object sender, Object to) in C:\Users\xxxxxx....\...\MainWindow.xaml.cs:line 1125
   at youtube.product.UserControl_MouseUp(Object sender, MouseButtonEventArgs e) in C:\Users\xxxxxx....\...\product.xaml.cs:line 239
   at System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
   at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
   at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
   at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   at System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)
   at System.Windows.UIElement.RaiseEvent(RoutedEventArgs args, Boolean trusted)
   at System.Windows.Input.InputManager.ProcessStagingArea()
   at System.Windows.Input.InputManager.ProcessInput(InputEventArgs input)
   at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
   at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)
   at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
   at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
   at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
   at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
   at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
   at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
   at System.Windows.Threading.Dispatcher.Run()
   at System.Windows.Application.RunDispatcher(Object ignore)
   at System.Windows.Application.RunInternal(Window window)
   at System.Windows.Application.Run(Window window)
   at System.Windows.Application.Run()
   at youtube.App.Main() in C:\Users\xxxxxx....\...\Debug\App.g.cs:line 0
   at System.AppDomain._nExecuteAssembly(RuntimeAssembly 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.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.ThreadHelper.ThreadStart()

here is detail of updatingItem

means,

    updatingItem.SearchKeywords = vInfo.SearchKeywords;
    updatingItem.SearchTimeStamp = DateTime.Now;

these codes are work.

by the meantime, VideoID is unique in my table then I cant add item which has same VideoID. But I want to update it. I think updating issue comes from here.

I don’t want to use sql commands.

I just want to update two fields of the table …

Answer 1

My guess is that when you call SaveChanges again on the same context it is trying to insert repeat the insert operation and fails again.

Calling ent.AcceptAllChanges() in the beginning of the catch block may work.

Maybe disposing the context and creating another one to use in the update function would be your easiest option. Otherwise, you will need to change the ObjectStateEntry.State to Unchanged for the two entities (videoinfo, process) you try to insert.