asp.net-mvc – 当多个用户创建用户时,修改了automapper错误集合

发布时间：2020-12-16 03:23:59 所属栏目：asp.Net 来源：网络整理

导读：我收到以下错误,只有当多个用户点击同一个按钮时才会出现此错误.任何帮助/想法将非常感激： System.InvalidOperationException: Collection was modified; enumeration operation may not execute. Generated: Wed,10 Jun 2015 07:29:06 GMT AutoMapper.Auto

我收到以下错误,只有当多个用户点击同一个按钮时才会出现此错误.任何帮助/想法将非常感激：

System.InvalidOperationException: Collection was modified; enumeration
operation may not execute. Generated: Wed,10 Jun 2015 07:29:06 GMT

AutoMapper.AutoMapperMappingException:

Mapping types: User -> User ApplicationSecurityManager.Service.User ->
ApplicationSecurityManager.Models.User

Destination path: User

Source value: ApplicationSecurityManager.Service.User —>
System.InvalidOperationException: Collection was modified; enumeration
operation may not execute. at
System.Collections.Generic.List1.Enumerator.MoveNextRare() at AutoMapper.TypeMap.<get_AfterMap>b__1(Object src,Object dest) at AutoMapper.Mappers.TypeMapObjectMapperRegistry.PropertyMapMappingStrategy.Map(ResolutionContext context,IMappingEngineRunner mapper) at AutoMapper.Mappers.TypeMapMapper.Map(ResolutionContext context, IMappingEngineRunner mapper) at AutoMapper.MappingEngine.AutoMapper.IMappingEngineRunner.Map(ResolutionContext context) --- End of inner exception stack trace --- at AutoMapper.MappingEngine.AutoMapper.IMappingEngineRunner.Map(ResolutionContext context) at AutoMapper.MappingEngine.Map[TDestination](Object source,Action1 opts) at
ApplicationSecurityManager.UserManager.LoadUser(String username) at
ApplicationSecurityManager.UserManager.get_AuthenticatedUser() at
ApplicationSecurityManager.UserManager.IsAuthenticated() at
ApplicationSecurityManager.Infrastructure.ApplicationSecurityAttribute.OnAuthorization(AuthorizationContext
filterContext) at
System.Web.Mvc.ControllerActionInvoker.InvokeAuthorizationFilters(ControllerContext
controllerContext,IList1 filters,ActionDescriptor actionDescriptor) at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass25.<BeginInvokeAction>b__1e(AsyncCallback asyncCallback,Object asyncState) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult1.Begin(AsyncCallback
callback,Object state,Int32 timeout) at
System.Web.Mvc.Async.AsyncResultWrapper.Begin[TResult](AsyncCallback
callback,BeginInvokeDelegate beginDelegate,
EndInvokeDelegate1 endDelegate,Object tag, EndInvokeDelegate1 endDelegate,Object tag) at
System.Web.Mvc.Controller.<>c__DisplayClass1d.b__17(AsyncCallback
asyncCallback,Object asyncState) at
System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult1.Begin(AsyncCallback callback,Int32 timeout) at System.Web.Mvc.Controller.BeginExecuteCore(AsyncCallback callback, Object state) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult1.Begin(AsyncCallback callback,Int32 timeout) at System.Web.Mvc.Async.AsyncResultWrapper.Begin(AsyncCallback callback, Object state,EndInvokeDelegate endDelegate,Object tag) at System.Web.Mvc.Controller.BeginExecute(RequestContext requestContext, AsyncCallback callback,Object state) at System.Web.Mvc.MvcHandler.<>c__DisplayClass8.b__2(AsyncCallback asyncCallback,Object tag) at System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContextBase httpContext,AsyncCallback callback,Object state) at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

 
 这是构造函数,我认为aftermap是问题,但在调试时我没有收到错误. 
  
 Public Sub New(environmentCode As String,applicationCode As String)
    MyBase.New(environmentCode,applicationCode)

    SOBaseUrl = System.Configuration.ConfigurationManager.AppSettings(Enums.AppSettingKeys.SOBaseUrl.ToString())
    If Not String.IsNullOrEmpty(SOBaseUrl) Then
        SOBaseUrl = SOBaseUrl.TrimEnd("/")
    End If

    'Setup mapping.
    Mapper.CreateMap(Of Service.User,Models.User)() _
        .ForMember(Function(dest As Models.User) dest.ENumber,Sub(opt) opt.MapFrom(Function(src As Service.User) src.INumber)) _
        .AfterMap(Sub(src As Service.User,dest As Models.User)

            dest.Groups = New List(Of String)

            Using service = ApplicationSecurityManager.Service.Factory.GetService()

                Dim applicationPermissions = service.LoadPermissionsForUser(dest.Username,MyBase.EnvironmentCode)

                If (Not applicationPermissions Is Nothing AndAlso applicationPermissions.Any(Function(x) x.Code = MyBase.ApplicationCode)) Then

                    dest.Groups = applicationPermissions.Single(Function(x) x.Code = MyBase.ApplicationCode).GroupNames.ToList()

                End If

            End Using

        End Sub) 
 Depenendency Injection Mapping： 
  
 container.RegisterType(Of IUserManager,UserManager)(New PerThreadLifetimeManager(),New InjectionConstructor(
      ConfigurationManager.AppSettings(Common.Enums.AppSettingKeys.Environment.ToString()),ConfigurationManager.AppSettings(Common.Enums.AppSettingKeys.ApplicationCode.ToString()))
    ) 
 在saveUserResponse中,错误被抛出. 
  
 Public Function Create(user As Common.Models.User,approve As Boolean) As SO.Common.Models.User Implements IUserProvider.Save

    Dim saveUserResponse = UserManager.SaveUser(Mapper.Map(Of ApplicationSecurityManager.Service.User)(user))

    If Not String.IsNullOrEmpty(saveUserResponse.ErrorMessage) Then

        'The Security system returned an error.

        Throw New Exception("Security Service returned error: " & saveUserResponse.ErrorMessage)

    End If

    'Return the username.
    Return Mapper.Map(Of Common.Models.User)(saveUserResponse.User)

End Function


解决方法

 当多个用户在映射的AfterMap()方法中修改相同的user.Groups集合时,会导致这种情况.要避免这种情况,请锁定正在处理集合的代码.例如： 
  
  
 'class level object
private object _myLock = New object()

'Setup mapping.
Mapper.CreateMap(Of Service.User,Models.User)() _
    .ForMember(Function(dest As Models.User) dest.ENumber,Sub(opt) opt.MapFrom(Function(src As Service.User) src.INumber)) _
    .AfterMap(Sub(src As Service.User,dest As Models.User)
                  SyncLock _myLock
                      dest.Groups = New List(Of String)

                      Using service = ApplicationSecurityManager.Service.Factory.GetService()

                          Dim applicationPermissions = service.LoadPermissionsForUser(dest.Username,MyBase.EnvironmentCode)

                          If (Not applicationPermissions Is Nothing AndAlso applicationPermissions.Any(Function(x) x.Code = MyBase.ApplicationCode)) Then

                              dest.Groups = applicationPermissions.Single(Function(x) x.Code = MyBase.ApplicationCode).GroupNames.ToList()

                          End If

                      End Using
                  End SyncLock

              End Sub)


            
        	


                        （编辑：李大同）
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