Entity Framework發生『Validation failed for one or more entities. See 'EntityValidationErrors' property for more details』

catch (DbEntityValidationException ex)

{

    var entityError = ex.EntityValidationErrors.SelectMany(x => x.ValidationErrors).Select(x => x.ErrorMessage);

    var getFullMessage = string.Join("; ", entityError);

    var exceptionMessage = string.Concat(ex.Message, "errors are: ", getFullMessage);

 //NLog

    LogException(new Exception(string.Format("File : {0} {1}.", logFile.FullName, exceptionMessage), ex));

}