c# - MySQL Entity Framework - 当多个元素作为参数传递时，Contains 方法会引发异常

Question

这里我使用Contains来创建IN语句:

public static List<Identity> GetIdentity(dbEntities db, string[] types)
{
    var query = (
     from au in db.user
     from c in db.career
     .Where(x => x.emp_nb == au.emp_nb).DefaultIfEmpty()
     .Where(x => types.Contains(x.type)) // here it is!
     select new Identity
     {
         userlogin = au.User_Login,
         first_name = au.User_First_Name,
         last_name = au.User_Last_Name,
     }
     ).Distinct();

    return query.ToList();
} 

当 types 数组只有一个元素时，这非常有效。

当在调试 session 期间它有两个或更多元素时，我得到:

Exception thrown at 0x00007FFDB3117788 (KernelBase.dll) in Migration_Module.exe: 0xC0000005: Access violation reading location 0x0000000000000018.

并且抛出异常:

System.NullReferenceException: 
   en MySql.Data.Entity.SelectStatement.AddDefaultColumns(Scope scope)
   en MySql.Data.Entity.SelectStatement.Wrap(Scope scope)
   en MySql.Data.Entity.SelectGenerator.Visit(DbApplyExpression expression)
   en MySql.Data.Entity.SqlGenerator.VisitInputExpression(DbExpression e, String name, TypeUsage type)
   en MySql.Data.Entity.SelectGenerator.VisitInputExpressionEnsureSelect(DbExpression e, String name, TypeUsage type)
   en MySql.Data.Entity.SelectGenerator.Visit(DbProjectExpression expression)
   en MySql.Data.Entity.SqlGenerator.VisitInputExpression(DbExpression e, String name, TypeUsage type)
   en MySql.Data.Entity.SelectGenerator.VisitInputExpressionEnsureSelect(DbExpression e, String name, TypeUsage type)
   en MySql.Data.Entity.SelectGenerator.Visit(DbDistinctExpression expression)
   en MySql.Data.Entity.SqlGenerator.VisitInputExpression(DbExpression e, String name, TypeUsage type)
   en MySql.Data.Entity.SelectGenerator.VisitInputExpressionEnsureSelect(DbExpression e, String name, TypeUsage type)
   en MySql.Data.Entity.SelectGenerator.Visit(DbProjectExpression expression)
   en MySql.Data.Entity.SelectGenerator.GenerateSQL(DbCommandTree tree)
   en MySql.Data.MySqlClient.MySqlProviderServices.CreateDbCommandDefinition(DbProviderManifest providerManifest, DbCommandTree commandTree)
   en System.Data.EntityClient.EntityCommandDefinition..ctor(DbProviderFactory storeProviderFactory, DbCommandTree commandTree)
   en System.Data.EntityClient.EntityProviderServices.CreateCommandDefinition(DbProviderFactory storeProviderFactory, DbCommandTree commandTree)
   en System.Data.Objects.Internal.ObjectQueryExecutionPlan.Prepare(ObjectContext context, DbQueryCommandTree tree, Type elementType, MergeOption mergeOption, Span span, ReadOnlyCollection`1 compiledQueryParameters, AliasGenerator aliasGenerator)
   en System.Data.Objects.ELinq.ELinqQueryState.GetExecutionPlan(Nullable`1 forMergeOption)
   en System.Data.Objects.ObjectQuery`1.GetResults(Nullable`1 forMergeOption)
   en System.Data.Objects.ObjectQuery`1.System.Collections.Generic.IEnumerable<T>.GetEnumerator()
   en System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   en System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   en SF_Migration_Module.queries.Queries.GetIdentity(dbEntities db, String[] types)

我正在使用:

• Visual Studio 2015
• Entity Framework 5
• MySQL NET 连接器 6.9.9

Answer 1

升级到 EntityFramework 6 解决了我的问题。

Install-Package EntityFramework
Install-Package MySql.Data.Entity -Version 6.9.9