With large amounts of data, it is not a good practice to pull all records from database when you are showing a fraction of them in one page. It is always recommended to use data on demand approach. When you want to show first 20 records out of the search results then you must get the first 20 records from database and discard the rest. Similarly when you want to show next 20 records of the search results then you need to get the next 20 records from database and discard the rest. This is nothing but called paging.
LINQ has made the paging solution very simple as shown below example.
GetAllClients(bool? isActive, int pageNumber, int pageSize, out int totalPages)
//Actual query which returns large data
var query = dataContext.Clients.Where(p => isActive == null || p.IsActive == isActive);
//Calculating total number of pages by taking ceiling number of the fractional value
totalPages = (int)Math.Ceiling((decimal)query.Count() / (decimal)pageSize);
//Paging logic goes here
return query.Skip((pageNumber - 1)*pageSize).Take(pageSize).ToList();
The parameters which play major role in paging are page number and page size. The page number is to identify the page of which the records to be returned. And the page size to identify the number of records to be returned. And there is another out parameter totalPages which is used to hold the total number of pages available within the data returned. This is needed to show the number of pages to the user and also useful in the logic which enables/disables page navigation.