C# Entity Framework Pagination

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Is there a way to get the row count of a complex Linq query and millions of records without hitting the db twice or writing 2 separate queries??

I might have my own suggestion. Write a stored procedure, but I'm good with MySQL not MSSQL.

Any better suggestions would be great. Also, if anyone knows if Microsoft is working on adding this feature to the entity framework.

I'd suggest using the Take() function. This can be used to specify the number of records to take from a linq query or List. For example

List<customers> _customers = (from a in db.customers select a).ToList();
var _dataToWebPage = _customers.Take(50);

I use a similar technique in an MVC app where I write the _customers list to the session and then use this list for further pagination queries when the user clicks on page 2, 3 etc. This saves multiple database hits. However if your list is very large then writing it too the session is probably not a good idea.

For pagination you can use the Skip() and Take() function together. For example to get page 2 of the data :

var _dataToWebPage = _customers.Skip(50).Take(50);

Tutorial: Add sorting, filtering, and paging with the Entity Framework , I'd suggest using the Take() function. This can be used to specify the number of records to take from a linq query or List. For example Tutorial: Add sorting, filtering, and paging with the Entity Framework in an ASP.NET MVC application. 01/14/2019; 14 minutes to read +4; In this article. In the previous tutorial, you implemented a set of web pages for basic CRUD operations for Student entities. In this tutorial you add sorting, filtering, and paging functionality to the

The common way to show millions of records is simply not to display all pages. Think of it: if you have millions of records, say 20 or even 100 items per page, then you'll have tens of thousands of pages. It does not make sense to show them all. You can simply load the current page and provide a link to the next page, that's it. Or you may load say 100-500 records, but still show only one page and use the loaded records information to generate page links for first several pages (so know for sure how many next pages are available).

C# Entity Framework Pagination, other entities such as Artist, Album, etc. public class Track { public int TrackId { get ; set; } public string� I use a similar technique in an MVC app where I write the _customers list to the session and then use this list for further pagination queries when the user clicks on page 2, 3 etc. This saves multiple database hits.

it is so easy on sql server . you can write this query :

select count() over(), table.* from table

the count () over() will return the count of total row in result , So you don't need to run two query.. Remember that you should run raw sql on your context or use dapper that return result as view model

Pagination with Entity Framework, Simple Entity Framework Core extension paging methods for IEnumerable and IQueryable interfaces. There's also method that maps entities to� Paging in Entity Framework Core If you’re using Entity Framework Core and building any non-trivial enterprise application then using data tables with paging is almost a certainty. There are two ways to do this: server side and client side. Which one you choose depends on your design and your needs.

I was recently inspired by (copied from) this Code Project article Entity Framework pagination

The code:

public async Task<IList<SavedSearch>> FindAllSavedSearches(int page, int limit)
{
    if (page == 0)
        page = 1;

    if (limit == 0)
        limit = int.MaxValue;

    var skip = (page - 1) * limit;

    var savedSearches = _databaseContext.SavedSearches.Skip(skip).Take(limit).Include(x => x.Parameters);
    return await savedSearches.ToArrayAsync();
}

I'm not experienced with Entity Framework and I've not tested it for performance, so use with caution :)

Paging with Entity Framework Core, I'd suggest using the Take() function. This can be used to specify the number of records to take from a linq query or List. For example Paging query results is timeless topic and some days ago I got question about how to do it with Entity Framework Core. Using my previous work on paging I wrote some simple extension methods that work with IQueryable<T> interface. There’s also method that maps entities to models. Paging classes. Let’s start with paging classes.

If you need a quick solution you can use XPagedList https://github.com/dncuug/X.PagedList. XPagedList is a library that enables you to easily take an IEnumerable/IQueryable, chop it up into "pages", and grab a specific "page" by an index. For example

var products = await _context.Products.ToPagedListAsync(pageNumber, pageSize)

C# Entity Framework Pagination, Pagination using Entity Framework through Web API. asp.net-mvc-3 asp.net-mvc- 4 c# c#-4.0 entity-� The following is an implementation of a simple extension method to offer paging functionality to simple Enitity framework or Linq to Sql query providers. /// < summary > /// Pages the specified query.

[SOLVED], If you're using Entity Framework Core and building any non-trivial This includes sorting, filtering, paging, and anything else that is done NET and C# aficionado with an interest in architecture, patterns, practices, and more. Adding ADO.NET Entity Framework Fig 5. Adding ADO.NET Entity Framework. After clicking on ADO.NET Entity Data Model, it will ask for the name of the ADO.NET Entity Data Model. We are going to name it “EfCustomer”. Fig 6. Specify Item Name. As soon as you click on OK button, a new wizard of Entity Data Model will appear.

Paging in Entity Framework Core, In Models folder, use the Entity Wizard to create Entity Data Model from Database in Visual Studio. This file use Entity Framework interact with� Tutorial: Add sorting, filtering, and paging - ASP.NET MVC with EF Core. 03/27/2019; 14 minutes to read +7; In this article. In the previous tutorial, you implemented a set of web pages for basic CRUD operations for Student entities.

Pagination with Entity Framework in ASP.NET MVC, Pagination In ASP.NET MVC and Entity Framework. Create Data Access and Business Logic Duration: 25:38 Posted: Jan 12, 2018 Sorting, Filtering, and Paging with the Entity Framework in an ASP.NET MVC Application (3 of 10) 07/30/2013; 22 minutes to read +4; In this article. by Tom Dykstra. Download Completed Project. The Contoso University sample web application demonstrates how to create ASP.NET MVC 4 applications using the Entity Framework 5 Code First and Visual

Comments
  • I quite confident you cannot get the number of rows in your query without either hitting the database or writing a query separate from the one that actually returns those rows.
  • Thanks @JonathanWood for your thoughts!
  • When you use .Count() in EF it does not select all rows, it only executes a select count() from table sql statement - so while you do need 2 queries, one of them is very cheap.
  • @JK select count() is not cheap at all! Actually it has almost the same complexity as actual fetching of data, the only difference is instead of fetching rows it only counts them. But it still have to perform all scans, etc.
  • If I have a complex query that just counts the results, which could be 10,000+, another that would just grabbed 20 of those results. Will Count() tax the entire process?
  • Thanks @TimNewton. Of course, but if I have a million records or better yet a thousand records with very large data columns you run into an out of memory exception.
  • Jason, you could consider writing the primary keys to a List in the session rather than the entire object, then retrieving the details from the database each time you need to redisplay the data using the primary keys from the list? This still requires multiple database reads though. I dont think you can get away without multiple db reads if you dataset is so large.
  • you might be right about not being able to make one db read for this instance in c# and using Linq. I know this can be done, its just that I want the ability to use Linq for that it's strongly typed and goes with the rest of my clean code. I have pagination working perfectly on smaller tables that don't hold large data sets or large data.
  • calling ToList() before Take(50) means you pull every record into your application. And then, after making the server do all that work, you ignore all but 50. Call Take(50) before ToList()
  • You are right, I would not want to show hundreds or thousands of links or even make someone step through that many pages. I guess the trouble I'm having is that I want to write just one query. For instance: MySQL allowed you to use SQL_CALC_FOUND_ROWS within a query and then another query to pull just that result. Very efficient!!! Made Pagination wonderful! Thanks @VladimirPerevalov for your thoughts!
  • AFAIK there is no such support in LINQ neither in MS SQL Server. Actually there are many things that MySql does and MS SQL does not. E.g. SELECT BETWEEN ... is also very effective for pagination.
  • you can also provide a text box "Go To:" and a button to jump to a specific page directly.
  • Actually, it is quite common to show some sort of pager controls that indicate the total number of pages/items.
  • @Jonathan Wood look at results from search engines for example. They show only ~10 pages. And an approximate number of total results (but is quite the other question).