Backend API
@(Html.DevExtreme().DataGrid() .ID("gridContainer") .ShowBorders(true) .CustomizeColumns(@<text> function(columns) { columns[0].width = 70; columns[4].dataType = "date"; } </text>) .LoadPanel(loadPanel => loadPanel.Enabled(true)) .Scrolling( scrolling => scrolling.Mode(GridScrollingMode.Virtual)) .Sorting(sorting => sorting.Mode(GridSortingMode.None)) .DataSource(d => d.WebApi().Controller("DataGridScrolling").Key("Id")) .OnContentReady("onContentReady") ) <script> function onContentReady(e) { e.component.option("loadPanel.enabled", false); } </script>
using DevExtreme.MVC.Demos.Models; using DevExtreme.MVC.Demos.Models.DataGrid; using DevExtreme.MVC.Demos.Models.SampleData; using System; using System.Linq; using System.Web.Mvc; namespace DevExtreme.MVC.Demos.Controllers { public class DataGridController : Controller { public ActionResult VirtualScrolling() { return View(); } } }
using DevExtreme.AspNet.Data; using DevExtreme.AspNet.Mvc; using DevExtreme.MVC.Demos.Models; using System; using System.Collections.Generic; using System.Net.Http; using System.Web.Http; namespace DevExtreme.MVC.Demos.Controllers.ApiControllers { public class DataGridScrollingController : ApiController { [HttpGet] public HttpResponseMessage Get(DataSourceLoadOptions loadOptions) { return Request.CreateResponse(DataSourceLoader.Load(GenerateData(100000), loadOptions)); } IEnumerable<User> GenerateData(int count) { var surnames = new[] { "Smith", "Johnson", "Brown", "Taylor", "Anderson", "Harris", "Clark", "Allen", "Scott", "Carter" }; var names = new[] { "James", "John", "Robert", "Christopher", "George", "Mary", "Nancy", "Sandra", "Michelle", "Betty" }; var gender = new[] { "Male", "Female" }; var startBirthDate = DateTime.Parse("1/1/1975"); var endBirthDate = DateTime.Parse("1/1/1992"); double s = 123456789; Func<double> random = () => { s = (1103515245 * s + 12345) % 2147483647; return s % (names.Length - 1); }; for(var i = 0; i < count; i++) { var birthDate = new DateTime(startBirthDate.Ticks + Convert.ToInt64(Math.Floor(random() * (endBirthDate.Ticks - startBirthDate.Ticks) / 10))); birthDate.AddHours(12); var nameIndex = Convert.ToInt32(random()); yield return new User { Id = i + 1, FirstName = names[nameIndex], LastName = surnames[Convert.ToInt32(random())], Gender = gender[Convert.ToInt32(Math.Floor(Convert.ToDouble(nameIndex / 5)))], BirthDate = birthDate }; } } } }
using System; using System.Collections.Generic; using System.Linq; using System.Web; namespace DevExtreme.MVC.Demos.Models { public class User { public int Id { get; set; } public string FirstName { get; set; } public string LastName { get; set; } public string Gender { get; set; } public DateTime BirthDate { get; set; } } }
#gridContainer { height: 440px; }
Unlike infinite scrolling, virtual scrolling allows users to navigate to any section of rows immediately. DataGrid only loads displayed rows into memory and unloads rows as they are hidden by user scrolling. When virtual scrolling is enabled, Ctrl+Home and Ctrl+End focus the first cell in the first row/last cell in the last row of the component data set.