我使用EF DbContext SqlQuery通过PagedList (https://github.com/TroyGoode/PagedList)获取分页对象的列表,并收到以下错误:
“该SqlParameter已被另一个SqlParameterCollection包含”
以下是我的存储库代码:
var db = (DbContext)DataContext;
const string sqlString =
@"
WITH UserFollowerList
AS
(
SELECT uf.FollowId
FROM UserFollow uf
WHERE uf.UserId = @UserId
)
SELECT * FROM UserFollowerList uf
INNER JOIN [User] u ON uf.FollowId = u.UserId
WHERE IsDeleted = 0
"
;
var userIdParam = new SqlParameter("UserId", SqlDbType.Int) {Value = userId};
var userList =
db.Database.SqlQuery<User>(sqlString, userIdParam)
.ToPagedList(pageIndex, pageSize);
return userList;但是,当我在SqlQuery语句上调用ToList扩展时,它工作得很好:
var userList = db.Database.SqlQuery<User>(sqlString, userIdParam).ToList();PagedList代码:
private PagedList(IQueryable<T> source, int pageIndex, int pageSize)
{
TotalItemCount = source.Count();
PageSize = pageSize;
PageIndex = pageIndex;
PageCount = TotalItemCount > 0 ? (int)Math.Ceiling(TotalItemCount / (double)PageSize) : 0;
HasPreviousPage = (PageIndex > 0);
HasNextPage = (PageIndex < (PageCount - 1));
IsFirstPage = (PageIndex <= 0);
IsLastPage = (PageIndex >= (PageCount - 1));
ItemStart = PageIndex * PageSize + 1;
ItemEnd = Math.Min(PageIndex * PageSize + PageSize, TotalItemCount);
// add items to internal list
if (TotalItemCount > 0)
Data = pageIndex == 0 ? source.Take(pageSize).ToList() : source.Skip((pageIndex) * pageSize).Take(pageSize).ToList();
}我已经有了下面的解决方案,但没有任何成功:
var param = new DbParameter[] { new SqlParameter { ParameterName = "UserId", Value = userId }我能做些什么来修复我遇到的错误?
发布于 2014-07-15 20:29:49
在使用诸如db.Database.SqlQuery之类的对SqlQuery的通用调用时,您必须迭代到返回集的最后一条记录,以便释放结果集和相关参数。PagedList使用source.Take(pageSize).ToList(),它不会读到源集的末尾。您可以通过在返回结果之前执行诸如foreach(userList中的用户x)之类的操作来解决此问题。
https://stackoverflow.com/questions/15308804
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