自动映射器显示错误“指定的转换无效。”

Question

i am getting error while mapping DataTable with the model

here is my code

       if (file.ContentLength > 0)
        {
            var extension = Path.GetExtension(file.FileName);
            if (extension != null && extension.ToLower() != ".xlsx")
            {
                return "please upload file with extension .xlsx";
            }

            Stream stream = file.InputStream;
            IExcelDataReader excelReader = ExcelReaderFactory.CreateOpenXmlReader(stream);
            excelReader.IsFirstRowAsColumnNames = true;
            DataSet result = excelReader.AsDataSet();
            if (result.Tables.Count > 0)
            {
                Mapper.Reset();
                Mapper.CreateMap<IDataReader, ExcelFeedbackRecord>();

                var results = Mapper.Map<IDataReader, IList<ExcelFeedbackRecord>>(result.Tables[0].CreateDataReader());

            }
            return result.Tables[0].Rows.Count.ToString();
        }

stack trace for error is below

  [InvalidCastException: Specified cast is not valid.] DynamicCreate(IDataRecord ) +1673 

AutoMapper.Mappers.DataReaderMapper.Map(ResolutionContext context, IMappingEngineRunner mapper) +433
AutoMapper.MappingEngine.AutoMapper.IMappingEngineRunner.Map(ResolutionContext context) +347

[AutoMapperMappingException: Trying to map System.Data.IDataReader to System.Collections.Generic.IList 1[[SkillKindle.BLL.Feedbacks.ExcelFeedbackRecord, SkillKindle.BLL, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]. Exception of type 'AutoMapper.AutoMapperMappingException' was thrown.]
AutoMapper.MappingEngine.AutoMapper.IMappingEngineRunner.Map(ResolutionContext context) +433 AutoMapper.MappingEngine.Map(Object source, Type sourceType, Type destinationType, Action 1[[SkillKindle.BLL.Feedbacks.ExcelFeedbackRecord, SkillKindle.BLL, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]. Exception of type 'AutoMapper.AutoMapperMappingException' was thrown.]
AutoMapper.MappingEngine.AutoMapper.IMappingEngineRunner.Map(ResolutionContext context) +433 AutoMapper.MappingEngine.Map(Object source, Type sourceType, Type destinationType, Action 1[[SkillKindle.BLL.Feedbacks.ExcelFeedbackRecord, SkillKindle.BLL, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]. Exception of type 'AutoMapper.AutoMapperMappingException' was thrown.]
AutoMapper.MappingEngine.AutoMapper.IMappingEngineRunner.Map(ResolutionContext context) +433 AutoMapper.MappingEngine.Map(Object source, Type sourceType, Type destinationType, Action 1 opts) +353
AutoMapper.MappingEngine.Map(TSource source) +564
AutoMapper.Mapper.Map(TSource source) +461
SkillKindleAdmin.Controllers.FeedbackController.ExcelUpload(HttpPostedFileBase file) in d:\\Skill Online\\trunk\\SkillKindleAdmin\\Controllers\\FeedbackController.cs:57
lambda_method(Closure , ControllerBase , Object[] ) +107
System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[] parameters) +286
System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary 2 parameters) +655
System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary 2 parameters) +655
System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary 2 parameters) +655
System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary 2 parameters) +326
System.Web.Mvc.Async.AsyncControllerActionInvoker.InvokeSynchronousActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary 2 parameters) +317
System.Web.Mvc.Async.<>c__DisplayClass42.<BeginInvokeSynchronousActionMethod>b__41() +219 System.Web.Mvc.Async.<>c__DisplayClass8 2 parameters) +317
System.Web.Mvc.Async.<>c__DisplayClass42.<BeginInvokeSynchronousActionMethod>b__41() +219 System.Web.Mvc.Async.<>c__DisplayClass8 2 parameters) +317
System.Web.Mvc.Async.<>c__DisplayClass42.<BeginInvokeSynchronousActionMethod>b__41() +219 System.Web.Mvc.Async.<>c__DisplayClass8 1.b__7(IAsyncResult ) +275 System.Web.Mvc.Async.WrappedAsyncResult 1.End() +328 System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +492
System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) +261
System.Web.Mvc.Async.<>c__DisplayClass39.<BeginInvokeActionMethodWithFilters>b__33() +268 System.Web.Mvc.Async.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49() +461 System.Web.Mvc.Async.<>c__DisplayClass37.<BeginInvokeActionMethodWithFilters>b__36(IAsyncResult asyncResult) +235 System.Web.Mvc.Async.WrappedAsyncResult 1.End() +328 System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +492
System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) +261
System.Web.Mvc.Async.<>c__DisplayClass39.<BeginInvokeActionMethodWithFilters>b__33() +268 System.Web.Mvc.Async.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49() +461 System.Web.Mvc.Async.<>c__DisplayClass37.<BeginInvokeActionMethodWithFilters>b__36(IAsyncResult asyncResult) +235 System.Web.Mvc.Async.WrappedAsyncResult 1.End() +328 System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +492
System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) +261
System.Web.Mvc.Async.<>c__DisplayClass39.<BeginInvokeActionMethodWithFilters>b__33() +268 System.Web.Mvc.Async.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49() +461 System.Web.Mvc.Async.<>c__DisplayClass37.<BeginInvokeActionMethodWithFilters>b__36(IAsyncResult asyncResult) +235 System.Web.Mvc.Async.WrappedAsyncResult 1.End() +328 System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +492
System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult) +262
System.Web.Mvc.Async.<>c _DisplayClass2a.b_ 20() +203 System.Web.Mvc.Async.<>c _DisplayClass25.b_ 22(IAsyncResult asyncResult) +392 System.Web.Mvc.Async.WrappedAsyncResult 1.End() +316 System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +387
System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +285
System.Web.Mvc.<>c__DisplayClass1d.<BeginExecuteCore>b__18(IAsyncResult asyncResult) +234
System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +275 System.Web.Mvc.Async.WrappedAsyncResult 1.End() +316 System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +387
System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +285
System.Web.Mvc.<>c__DisplayClass1d.<BeginExecuteCore>b__18(IAsyncResult asyncResult) +234
System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +275 System.Web.Mvc.Async.WrappedAsyncResult 1.End() +316 System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +387
System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +285
System.Web.Mvc.<>c__DisplayClass1d.<BeginExecuteCore>b__18(IAsyncResult asyncResult) +234
System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +275 System.Web.Mvc.Async.WrappedAsyncResult 1.End() +333
System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +397
System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +266
System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +253 System.Web.Mvc.Async.<>c _DisplayClass4.b__3(IAsyncResult ar) +275 System.Web.Mvc.Async.WrappedAsyncResult 1.End() +333
System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +397
System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +266 System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +254
System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +226
System.Web.Mvc.<>c__DisplayClass8.<BeginProcessRequest>b__3(IAsyncResult asyncResult) +230
System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +275 System.Web.Mvc.Async.WrappedAsyncResult 1.End() +333
System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +397
System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +266 System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +254
System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +226
System.Web.Mvc.<>c__DisplayClass8.<BeginProcessRequest>b__3(IAsyncResult asyncResult) +230
System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +275 System.Web.Mvc.Async.WrappedAsyncResult 1.End() +333
System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +397
System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +266 System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +254
System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +226
System.Web.Mvc.<>c__DisplayClass8.<BeginProcessRequest>b__3(IAsyncResult asyncResult) +230
System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +275 System.Web.Mvc.Async.WrappedAsyncResult 1.End() +333
System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +397
System.Web.Mvc.Async.AsyncResultWrapper.End(IAsyncResult asyncResult, Object tag) +266
System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +255 System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +225
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +1086 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +603

Answer 1

Are you sure the columns returned by the datareader exactly match the property fields in the object ExcelFeedbackRecord, including casing? If they are not, you'll have to add a configuration when creating the map.

Answer 2

很好的问题是，当我们将DataSet与模型映射时，模型的所有属性都必须仅是字符串类型，然后可以使用automapper的CustomTypeConversion方法。