更新条目时发生错误.有关详细信息,请参阅内部异常 - Linq to Entity

Question

一直在环顾四周,我似乎无法弄清楚出了什么问题.

目前我正试图在玩家死亡时用新的高分来更新我的数据库.但无论我选择尝试和保存,它都会向我抛出异常.

码:

 HighScore hs = new HighScore();
            var id = from i in db.HighScores
                     orderby i.ID descending
                     select i;
            int newId = 0;

            if (id.Count() == 0)
            {
                newId = 1;
            }
            else
            {
                newId = id.First().ID + 1;
            }
        hs.ID = 6; //I just hardcoded in 6 to make sure i wasent because of the newId      //thing, and i have checked if theres already something on the sixths spot as well.
            hs.UserHighscore = 100;
            hs.HighscoreUsername = "test";
            hs.GameID = 1;
            db.HighScores.AddObject(hs);
            db.SaveChanges();

我一次又一次地检查过,我似乎无法弄清问题是什么.

任何帮助都会得到满足.

例外:

System.Data.UpdateException was unhandled
  Message=An error occurred while updating the entries. See the inner exception for details.
  Source=System.Data.Entity
  StackTrace:
       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 MatematikSpilMenu.SaveBunniesSceen.SaveHighscore() in MatematikSpilMenu\SaveBunniesSceen.cs:line 173
       at MatematikSpilMenu.SaveBunniesSceen.Update(GameTime gameTime, Boolean otherScreenIsActive, Boolean coveredByOtherScreens) in C:\Users\Etarnalazure-Alien\documents\visual studio 2010\Projects\MatematikSpilMenu\MatematikSpilMenu\MatematikSpilMenu\SaveBunniesSceen.cs:line 110
       at MatematikSpilMenu.ScreenManager.Update(GameTime gameTime) in MatematikSpilMenu\ScreenManager.cs:line 101
       at Microsoft.Xna.Framework.Game.Update(GameTime gameTime)
       at Microsoft.Xna.Framework.Game.Tick()
       at Microsoft.Xna.Framework.Game.HostIdle(Object sender, EventArgs e)
       at Microsoft.Xna.Framework.GameHost.OnIdle()
       at Microsoft.Xna.Framework.WindowsGameHost.RunOneFrame()
       at Microsoft.Xna.Framework.WindowsGameHost.ApplicationIdle(Object sender, EventArgs e)
       at System.Windows.Forms.Application.ThreadContext.System.Windows.Forms.UnsafeNativeMethods.IMsoComponent.FDoIdle(Int32 grfidlef)
       at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr 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 Microsoft.Xna.Framework.WindowsGameHost.Run()
       at Microsoft.Xna.Framework.Game.RunGame(Boolean useBlockingRun)
       at Microsoft.Xna.Framework.Game.Run()
       at MatematikSpilMenu.Program.Main() in MatematikSpilMenu\Game1.cs:line 120
  InnerException: System.Data.EntityCommandCompilationException
       Message=An error occurred while preparing the command definition. See the inner exception for details.
       Source=System.Data.Entity
       StackTrace:
            at System.Data.Mapping.Update.Internal.UpdateTranslator.CreateCommand(DbModificationCommandTree commandTree)
            at System.Data.Mapping.Update.Internal.DynamicUpdateCommand.CreateCommand(UpdateTranslator translator, Dictionary`2 identifierValues)
            at System.Data.Mapping.Update.Internal.DynamicUpdateCommand.Execute(UpdateTranslator translator, EntityConnection connection, Dictionary`2 identifierValues, List`1 generatedValues)
            at System.Data.Mapping.Update.Internal.UpdateTranslator.Update(IEntityStateManager stateManager, IEntityAdapter adapter)
       InnerException: System.NotSupportedException
            Message=Server-generated keys and server-generated values are not supported by SQL Server Compact.
            Source=System.Data.SqlServerCe.Entity
            StackTrace:
                 at System.Data.SqlServerCe.SqlGen.DmlSqlGenerator.GenerateReturningSql(StringBuilder commandText, DbModificationCommandTree tree, ExpressionTranslator translator, DbExpression returning)
                 at System.Data.SqlServerCe.SqlGen.DmlSqlGenerator.GenerateInsertSql(DbInsertCommandTree tree, List`1& parameters, Boolean isLocalProvider)
                 at System.Data.SqlServerCe.SqlGen.SqlGenerator.GenerateSql(DbCommandTree tree, List`1& parameters, CommandType& commandType, Boolean isLocalProvider)
                 at System.Data.SqlServerCe.SqlCeProviderServices.CreateCommand(DbProviderManifest providerManifest, DbCommandTree commandTree)
                 at System.Data.SqlServerCe.SqlCeProviderServices.CreateDbCommandDefinition(DbProviderManifest providerManifest, DbCommandTree commandTree)
                 at System.Data.Common.DbProviderServices.CreateCommandDefinition(DbCommandTree commandTree)
                 at System.Data.Common.DbProviderServices.CreateCommand(DbCommandTree commandTree)
                 at System.Data.Mapping.Update.Internal.UpdateTranslator.CreateCommand(DbModificationCommandTree commandTree)
            InnerException: 

Answer 1

根据我的经验,通常由db错误触发,在我的情况下,它是与失败的表相关联的触发器并抛出根异常.但是,在您的情况下,您似乎错误地尝试在使用自动编号(标识)字段时手动定义id.

Answer 2

在我看来，问题的根源在于您使用的 SQL 服务器：

SQL Server Compact 不支持服务器生成的键和服务器生成的值。

您是否尝试在 SQL Server Compact 版本上使用自动增量 ID？我不太记得了，但也许那个 SQL 版本是不可能的。我建议你先检查一下。