c# - FormatException : The string was not recognized as a valid DateTime. 有一个从索引 0 开始的未知单词

Question

我花了 4 天时间试图让 EF Core 为记录保存日期时间值。 它一直失败并出现以下错误:

FormatException:字符串未被识别为有效的 DateTime。有一个从索引 0 开始的未知单词。

我看了将近一百篇关于类似无济于事的帖子。我尝试了多种日期时间格式。下面是 Visual Studio 中最新尝试的链接，其中一些 watch 设置了相关值。

    var format = "yyyy-MM-dd HH:mm:ss.fff";
    var stringDate = DateTime.Now.ToString(format);
    gl.LastUpdate =DateTime.ParseExact(stringDate,format,CultureInfo.InvariantCulture);
    db.SaveChanges(); //Entity Framework Core

        //model snip
        [Display(Name = "Updated Date")]
        public  DateTime? LastUpdate { get; set; }

我试图找到 EF Core 期望的日期时间格式的文档，但没有成功。

由于这个错误，我无法保存我的记录。我认为它必须是相对简单的东西，希望有人能对此有所启发。

异常详细信息

Microsoft.EntityFrameworkCore.DbUpdateException: An error occurred while updating the entries. See the inner exception for details. ---> System.FormatException: Failed to convert parameter value from a String to a DateTime. ---> System.FormatException: The string was not recognized as a valid DateTime. There is an unknown word starting at index 0.
at System.DateTimeParse.Parse(String s, DateTimeFormatInfo dtfi, DateTimeStyles styles)
at System.Convert.ToDateTime(String value, IFormatProvider provider)
at System.Convert.ChangeType(Object value, Type conversionType, IFormatProvider provider)
at System.Data.SqlClient.SqlParameter.CoerceValue(Object value, MetaType destinationType, Boolean& coercedToDataFeed, Boolean& typeChanged, Boolean allowStreaming)
--- End of inner exception stack trace ---
at System.Data.SqlClient.SqlParameter.CoerceValue(Object value, MetaType destinationType, Boolean& coercedToDataFeed, Boolean& typeChanged, Boolean allowStreaming)
at System.Data.SqlClient.SqlParameter.GetCoercedValue()
at System.Data.SqlClient.SqlParameter.Validate(Int32 index, Boolean isCommandProc)
at System.Data.SqlClient.SqlCommand.BuildParamList(TdsParser parser, SqlParameterCollection parameters)
at System.Data.SqlClient.SqlCommand.BuildExecuteSql(CommandBehavior behavior, String commandText, SqlParameterCollection parameters, _SqlRPC& rpc)
at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async, Int32 timeout, Task& task, Boolean asyncWrite, SqlDataReader ds)
at System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior)
at Microsoft.EntityFrameworkCore.Storage.Internal.RelationalCommand.Execute(IRelationalConnection connection, String executeMethod, IReadOnlyDictionary 2 parameterValues, Boolean closeConnection) 在 Microsoft.EntityFrameworkCore.Storage.Internal.RelationalCommand.ExecuteReader(IRelationalConnection 连接，IReadOnlyDictionary 2 parameterValues)
at Microsoft.EntityFrameworkCore.Update.ReaderModificationCommandBatch.Execute(IRelationalConnection connection)
--- End of inner exception stack trace ---
at Microsoft.EntityFrameworkCore.Update.ReaderModificationCommandBatch.Execute(IRelationalConnection connection)
at Microsoft.EntityFrameworkCore.Update.Internal.BatchExecutor.Execute(Tuple 2 个参数) 在 Microsoft.EntityFrameworkCore.Storage.Internal.SqlServerExecutionStrategy.Execute[TState,TResult](Func 2 operation, Func 2 verifySucceeded, TState 状态) 在 Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChanges(IReadOnlyList 1 entriesToSave)
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChanges(Boolean acceptAllChangesOnSuccess)
at Microsoft.EntityFrameworkCore.DbContext.SaveChanges(Boolean acceptAllChangesOnSuccess)
at TMain.Models.TmainContext.SaveChanges() in C:\Users\dmcquay\Source\Workspaces\SCM\NET Core\TMainModel\Models\tmainContext.cs:line 123
at TMain.Data.GLConfigurationRepository.SaveChanges() in C:\Users\dmcquay\Source\Workspaces\SCM\NET Core\TMainModel\Data\GLConfigurationRepository.cs:line 40
at GLCoderConfiguration.Controllers.GLConfigController.Save(Int32 id, String userName) in C:\Users\dmcquay\Source\Workspaces\SCM\NET Core\GLCoderConfiguration\Controllers\GLConfigController.cs:line 181
at lambda_method(Closure , Object , Object[] )
at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeActionMethodAsync>d__27.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeNextActionFilterAsync>d__25.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Rethrow(ActionExecutedContext context)
at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeNextResourceFilter>d__22.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Rethrow(ResourceExecutedContext context)
at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeAsync>d__20.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.AspNetCore.Builder.RouterMiddleware.<Invoke>d__4.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.AspNetCore.Session.SessionMiddleware.<Invoke>d__9.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at Microsoft.AspNetCore.Session.SessionMiddleware.<Invoke>d__9.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.VisualStudio.Web.BrowserLink.BrowserLinkMiddleware.<ExecuteWithFilter>d__7.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.<Invoke>d__7.MoveNext()

Answer 1

更改第二行。您不能在 ToString 方法调用中使用带有 {0: 前缀的格式字符串:

var stringDate = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss.fff");