System.InvalidCastException: Specified cast is not valid.
at System.Data.Linq.SqlClient.SqlProvider.Execute(Expression query, QueryInfo queryInfo, IObjectReaderFactory factory, Object[] parentArgs, Object[] userArgs, ICompiledSubQuery[] subQueries, Object lastResult)
at System.Data.Linq.SqlClient.SqlProvider.ExecuteAll(Expression query, QueryInfo[] queryInfos, IObjectReaderFactory factory, Object[] userArguments, ICompiledSubQuery[] subQueries)
at System.Data.Linq.SqlClient.SqlProvider.System.Data.Linq.Provider.IProvider.Execute(Expression query)
at System.Data.Linq.DataQuery`1.System.Linq.IQueryProvider.Execute[S](Expression expression)
at System.Linq.Queryable.FirstOrDefault[TSource](IQueryable`1 source)
at System.Web.Mvc.PathExtensions.ThumbUrl[T](T entity, Int32 size)
at CompiledRazorTemplates.Dynamic.abdabcabaed.Execute()
at RazorEngine.Templating.TemplateBase.Run(ExecuteContext context)
at System.Web.Mvc.HtmlTemplateBase`1.Run(ExecuteContext context)
at CMS.Core.ITemplateExtensions.Run[T](ITemplate template, T Model)
at CMS.Core.ITemplateExtensions.Parse[T](String template, T Model)
@{var books = ERP.Data.DBContext.Current.Product.Active().OrderByDescending(i => i.DateUpdated).ToList();}

Recently Updated Books

Error:
Specified cast is not valid.
@{ var db = ERP.Data.DBContext.Current; var authors = db.Party.Active().Where(p => p.TypeId == 1017 && db.PartyProduct.Any(i => i.PartyId == p.Id)); var books = ERP.Data.DBContext.Current.Product.Active(); }

A National Archive of Information

@ERP.Data.Service.BusinessService.ByType("Publisher").Count()

Publishers

Featuring complete portfolio & virtual showroom of @ERP.Data.Service.BusinessService.ByType("Publisher").Count() active Publishers in Bangladesh.

@authors.Count().ToString("#,###")

Authors

Portfolio of an ever growing list of legends. About 3,000 Bengali authors & Poets of the past, present & future.

@books.Count().ToString("#,###")

Books

A complete online catalog of Bangla books. From the everlasting classics to modern literature of the future generation.

Error:
Unable to cast object of type 'System.Int32' to type 'System.String'.