C# LINQ：查询结果不能枚举多次
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LINQ : The query results cannot be enumerated more than once
提问by 8611670474
This is my code
这是我的代码
searchDataContext db = new searchDataContext();
var query = (from p in db.SearchFirst(city, area)
select new
{
ID = p.Id,
Address = p.address,
Level = p.agahilevel
});
int count =query.Count();
// records
var q = query.Skip(Convert.ToInt32(start)).Take(Convert.ToInt32(width));
if (q.Count() > 0)
{
int index = 0;
str += "[";
foreach (var row in q)
{
if (index == 0)
I have an error in this code
我在这段代码中有一个错误
The query results cannot be enumerated more than once.
please check that and answer me.
请检查并回答我。
采纳答案by Tim Schmelter
Materialize your query:
实现您的查询：
var addresses = (from p in db.SearchFirst(city, area)
select new
{
ID = p.Id,
Address = p.address,
Level = p.agahilevel
})
.Skip(Convert.ToInt32(start))
.Take(Convert.ToInt32(width))
.ToList();
Then use Enumerable.Anyto check if it contains elements:
然后用于Enumerable.Any检查它是否包含元素：
if(addresses.Any())
{
int index = 0; // ...
}
回答by bash.d
You cannot use cached queries and iterate over them more than once...
Make a List<T>of it and try it again
您不能使用缓存查询并多次迭代它们...
制作并重List<T>试
var q = query.ToList(); // work on this
回答by Maryam Arshi
If you add .ToList()to your query your problem will be solved
如果您添加.ToList()到查询中，您的问题将得到解决
