如何转换system.linq.IQueryable <int?> 诠释？[]

Question

foreach (var app in allList)
{
    int?[] ids = Context.tblTransactionDetails
        .Where(x => x.IsActive == true)
        .Select(x => x.AdvertID);
}

Answer 1

In C#, T[] designates an array of elements of type T . In order to obtain an array from a sequence, use ToArray() extension method:

foreach (var app in allList)
{
    int?[] ids = Context.tblTransactionDetails
        .Where(x => x.IsActive == true)
        .Select(x => x.AdvertID)
        .ToArray();
}

Note that this will evaluate the expression and load all the elements of the sequence to memory. If you don't need all the elements at the same time (in most cases, you really don't), this may not be what you want.