从列表中删除项目

Question

why cant I select remove or delete? I want to remove a record from a list

IEnumerable<StockLocation_Table> AllCurrentStocklocations = db.StockLocation_Table.ToList();
List<StockLocation> StockLocations = ServerHelper.GetStockLocationsBatch(BatchUrl, i, batchSize);

foreach (StockLocation_Table _stock_table in AllCurrentStocklocations)
{
    foreach (StockLocation _stock in StockLocations)
    {
        if (_stock.ServerLocationId == _stock_table.ServerLocationId)
        {
            AllCurrentStocklocations.?? why cant i say remove._stock_table 
        }
    }
}

Answer 1

Because it is IEnumerable<T> and the Remove method is not defined in IEnumerable<T> .Since you are using ToList just use a List<T> as type:

List<StockLocation_Table> AllCurrentStocklocations = db.StockLocation_Table.ToList();

Edit: Also you can't modify the collection inside of foreach loop.You can use LINQ instead:

var AllCurrentStocklocations = db.StockLocation_Table
                    .Where(x => !StockLocations
                    .Any(s => s.ServerLocationId == x.ServerLocationId).ToList()

Answer 2

What you want to do here is get all of the items from your DB table where the ID is not in this other list. What you should do here is construct a query such that you get just those items without those IDs, rather than pulling down the entire DB table into a list, and then going through this other list for each item ) to look for IDs so that you can remove the current item from this list. In addition to being super inefficient, this would also mean removing the item from a collection being iterated, which would break the iterator. Instead write something that can be translated into a DB query:

List<StockLocation> stockLocations = ServerHelper.GetStockLocationsBatch(
    BatchUrl, i, batchSize);
var locationIDs = stockLocations.Select(location => location.ServerLocationId);
db.StockLocation_Table.Where(item => 
    !locationIDs.Contains(item.ServerLocationId));