我基本上是：
public ActionResult MyAction(List<int> myIds)
{
var myList = from entry in db.Entries
where (myIds == null || myIds.Contains(entry.Id))
select entry;
return View(myList);
}
目的是仅获取带有传递ID的项目或返回所有这些项目. (其他标准为了清楚而剪除)
当我返回myList时,我收到异常,我已经做了一些调试,并且发生在.ToList()
Cannot compare elements of type ‘System.Collections.Generic.List`1’.
Only primitive types (such as Int32,String,and Guid) and entity
types are supported.
解决方法
问题是因为myIds是空的.
我需要：
public ActionResult MyAction(List<int> myIds)
{
if(myIds == null)
{
myIds = new List<int>();
}
bool ignoreIds = !myIds.Any();
var myList = from entry in db.Entries
where (ignoreIds || myIds.Contains(entry.Id))
select entry;
return View(myList);
}
