请教.net mvc 中linq如何实现这个功能？
0
悬赏园豆：20
[已解决问题]
解决于 2011-01-20 17:52
最近参考网上代码：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data.Linq;
namespace WMVC.Models
{
public class RepositoryTest<T> where T : class
{
public DataContext context;
public RepositoryTest(DataContext context)
{
this.context = context;
}
public IEnumerable<T> FindAll(Func<T, bool> exp)
{
return context.GetTable<T>().Where(exp);
}
}
}
可以实现：
DataContext content = new MyDataContext();
RepositoryTest rp = new RepositoryTest<my_tbl>(DataContext);
rp.FindAll(t => t.name == "jack"));
return View(rp);
那么下面我想实现：
DataContext content = new MyDataContext();
RepositoryTest rp = new RepositoryTest<my_tbl>(DataContext);
rp.FindAll(1,t => t.name == "jack")); //这里多加了一个条件
return View(rp);
我修改了代码如下，但是无法编译，请教各位前辈应该如何修改，谢谢！
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data.Linq;
namespace WMVC.Models
{
public class RepositoryTest<T> where T : class
{
public DataContext context;
public RepositoryTest(DataContext context)
{
this.context = context;
}
public IEnumerable<my_tbl> FindAll(int pid, Func<my_tbl, bool> exp)
{
var result = from a in context.GetTable<my_tbl>()
where a.parent_id == pid
select a;
//result.Where(t=>t.name == "jack"); 可通过
//result.Where(exp); 出错
return result;
}
}
}
实际方法定义代码如下：
public IEnumerable<MenuClasses> listBom(int? id,Func<MenuClasses, bool> exp)
{
id = id == null ? 0 : id;
SourceClassDataContext s = (SourceClassDataContext)context;
var result = from a in s.GetTable<tbl_SourceClasses>()
join b in s.class_f_Cid(id) on
a.id equals b.id into prods
from b in prods
orderby b.temp_orderby
select new MenuClasses()
{
id = a.id,
parent_id = a.parent_id,
class_order = a.class_order,
class_name = a.class_name,
temp_orderby = b.temp_orderby,
Level = b.Level
};
//result = result.Where(b => b.Level == 1); //可通过
//result = result.Where<MenuClasses>(exp); //无法通过
return result;
}
最佳答案
0
应该用IQueryable<T>
然后rp.Where(p=>p.Pid=1).Where(p=>p.Name="2131")
这个和以下等价 rp.Where(p=>p.Pid=1&& p.Name="2131")
收获园豆：20
因为查询使用了mssql的自定义函数，而且查询比较复杂，所以我想把一部分查询语法封装到Repository里面
完整方法代码如下：
public IEnumerable<MenuClasses> listBom(int? id,Func<MenuClasses, bool> exp)
{
id = id == null ? 0 : id;
SourceClassDataContext s = (SourceClassDataContext)context;
var result = from a in s.GetTable<tbl_SourceClasses>()
join b in s.class_f_Cid(id) on
a.id equals b.id into prods
from b in prods
orderby b.temp_orderby
select new MenuClasses()
{
id = a.id,
parent_id = a.parent_id,
class_order = a.class_order,
class_name = a.class_name,
temp_orderby = b.temp_orderby,
Level = b.Level
};
//result = result.Where(b => b.Level == 1); //可通过
//result = result.Where<MenuClasses>(exp); //无法通过 return result;
}
好乱，我补充到问题后面了！