实体框架SaveChanges错误详细信息

Question

在SaveChanges数据上下文中保存更改时,有没有办法确定哪个实体导致错误？例如,有时我会忘记将日期分配给不可为空的日期字段并获得"无效日期范围"错误,但我没有得到关于它由哪个实体或哪个字段引起的信息(我通常可以通过以下方式跟踪它煞费苦心地经历我的所有物品,但这是非常耗时的).堆栈跟踪非常无用,因为它只会在SaveChanges调用时向我显示错误,而没有任何关于它究竟发生在何处的其他信息.

请注意,我不打算解决我现在遇到的任何特定问题,我只想知道是否有办法告诉哪个实体/字段导致问题.

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以堆栈跟踪的快速示例为例 - 在这种情况下发生错误,因为CreatedOn未在IAComment实体上设置日期,但是无法从此错误/堆栈跟踪中判断

    [SqlTypeException: SqlDateTime overflow. Must be between 1/1/1753 12:00:00 AM and 12/31/9999 11:59:59 PM.]
   System.Data.SqlTypes.SqlDateTime.FromTimeSpan(TimeSpan value) +2127345
   System.Data.SqlTypes.SqlDateTime.FromDateTime(DateTime value) +232
   System.Data.SqlClient.MetaType.FromDateTime(DateTime dateTime, Byte cb) +46
   System.Data.SqlClient.TdsParser.WriteValue(Object value, MetaType type, Byte scale, Int32 actualLength, Int32 encodingByteSize, Int32 offset, TdsParserStateObject stateObj) +4997789
   System.Data.SqlClient.TdsParser.TdsExecuteRPC(_SqlRPC[] rpcArray, Int32 timeout, Boolean inSchema, SqlNotificationRequest notificationRequest, TdsParserStateObject stateObj, Boolean isCommandProc) +6248
   System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async) +987
   System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result) +162
   System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method) +32
   System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior, String method) +141
   System.Data.SqlClient.SqlCommand.ExecuteDbDataReader(CommandBehavior behavior) +12
   System.Data.Common.DbCommand.ExecuteReader(CommandBehavior behavior) +10
   System.Data.Mapping.Update.Internal.DynamicUpdateCommand.Execute(UpdateTranslator translator, EntityConnection connection, Dictionary`2 identifierValues, List`1 generatedValues) +8084396
   System.Data.Mapping.Update.Internal.UpdateTranslator.Update(IEntityStateManager stateManager, IEntityAdapter adapter) +267

[UpdateException: An error occurred while updating the entries. See the inner exception for details.]
   System.Data.Mapping.Update.Internal.UpdateTranslator.Update(IEntityStateManager stateManager, IEntityAdapter adapter) +389
   System.Data.EntityClient.EntityAdapter.Update(IEntityStateManager entityCache) +163
   System.Data.Objects.ObjectContext.SaveChanges(SaveOptions options) +609
   IADAL.IAController.Save(IAHeader head) in C:\Projects\IA\IADAL\IAController.cs:61
   IA.IAForm.saveForm(Boolean validate) in C:\Projects\IA\IA\IAForm.aspx.cs:198
   IA.IAForm.advance_Click(Object sender, EventArgs e) in C:\Projects\IA\IA\IAForm.aspx.cs:287
   System.Web.UI.WebControls.Button.OnClick(EventArgs e) +118
   System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +112
   System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10
   System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13
   System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +36
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +5019

Answer 1

一种选择是处理ObjectContext.SavingChanges事件,它使您有机会在保存更改之前对实体执行验证,甚至在必要时取消保存.这样,您可以确保在尝试保存更改之前设置了任何非可空属性,并避免必须依赖异常处理.