C# “如何绕过”不能使用两个查询多次枚举
下面的代码正在第二个ToList()上抛出“不能枚举多次”。修复此错误的最佳方法是什么C# “如何绕过”不能使用两个查询多次枚举,c#,C#,下面的代码正在第二个ToList()上抛出“不能枚举多次”。修复此错误的最佳方法是什么 var firstQuery = (from r in db.SomeProcedure(Id) select new MyClass { Id = r.Id, Name = r.Name,
var firstQuery = (from r in db.SomeProcedure(Id)
select new MyClass
{
Id = r.Id,
Name = r.Name,
Company= r.Company,
Title = r.Title
});
var secondQuery = (from d in firstQuery
group d by d.Title into groupedTitles
select new MyClass2
{
Title = groupedTitles.Key, //How To include the Id
});
List<MyClass> mClass = firstQuery.ToList();
Th Below ToList() is throwing a cannot enumerate more than one
List<MyClass2> mClass2 = secondQuery.ToList();
var firstQuery=(来自db.SomeProcedure(Id)中的r)
选择新MyClass
{
Id=r.Id,
Name=r.Name,
公司,
头衔
});
var secondQuery=(来自firstQuery中的d
按d分组。标题分为分组标题
选择新MyClass2
{
Title=groupedTitles.Key,//如何包含Id
});
List mClass=firstQuery.ToList();
下面的Th ToList()正在抛出一个,不能枚举多个
List mClass2=secondQuery.ToList();
如何修复错误?立即将第一个查询转换为列表
var firstQuery = (from r in db.SomeProcedure(Id)
select new MyClass
{
Id = r.Id,
Name = r.Name,
Company= r.Company,
Title = r.Title
}).ToList();
var secondQuery = (from d in firstQuery
group d by d.Title into groupedTitles
select new MyClass2
{
Title = groupedTitles.Key, //How To include the Id
});
List<MyClass> mClass = firstQuery;
List<MyClass2> mClass2 = secondQuery.ToList();
var firstQuery=(来自db.SomeProcedure(Id)中的r)
选择新MyClass
{
Id=r.Id,
Name=r.Name,
公司,
头衔
}).ToList();
var secondQuery=(来自firstQuery中的d
按d分组。标题分为分组标题
选择新MyClass2
{
Title=groupedTitles.Key,//如何包含Id
});
List mClass=firstQuery;
List mClass2=secondQuery.ToList();
这将不支持第二个查询的服务器端查询。@确实是usr-这是一个限制。