MVC Basic Site: Step 3 – Dynamic Layouts and Site Admin with: AJAX, jqGrid, Controller Extensions, HTML Helpers, and more

using System;
using System.Linq;
using System.Web.Mvc;
using System.Data.Objects;
//
using System.Collections.Generic;

namespace MvcBasicSite.Models.Grid
{
    /// <summary>
    /// Defines the jqGrid settings.
    /// </summary>
    /// <remarks>
    /// These settings are used for paging and sorting of the grid data.
    /// </remarks>
    [ModelBinder(typeof(GridModelBinder))]
    [Serializable]
    public class GridSettings
    {
        /// <summary>
        /// Gets or sets the page size.
        /// </summary>
        public int PageSize { get; set; }
        /// <summary>
        /// Gets or sets the page index.
        /// </summary>
        public int PageIndex { get; set; }
        /// <summary>
        /// Gets or sets the sort column.
        /// </summary>
        public string SortColumn { get; set; }
        /// <summary>
        /// Gets or sets the sort order.
        /// </summary>
        public string SortOrder { get; set; }
        
        /// <summary>
        /// Initializes a new instance of the GridSettings class.
        /// </summary>
        public GridSettings()
        {
            this.SortColumn = "ID";
            this.SortOrder = "DESC";
            this.PageIndex = 1;
            this.PageSize = 20;
        }

        /// <summary>
        /// Initializes a new instance of the GridSettings class.
        /// </summary>
        /// <param name="sortColumn">The sort column.</param>
        /// <param name="ascending">Sort ascending flag.</param>
        public GridSettings(string sortColumn, bool ascending)
        {
            this.SortColumn = sortColumn;
            this.SortOrder = (ascending ? "ASC" : "DESC");
            this.PageIndex = 1;
            this.PageSize = 20;
        }

        /// <summary>
        /// Initializes a new instance of the GridSettings class.
        /// </summary>
        /// <param name="stringData">The string that represents the a GridSettings object.</param>
        public GridSettings(string stringData)
        {
            string[] tempArray = stringData.Split(new string[] { "#;" }, StringSplitOptions.None);
            this.PageSize = int.Parse(tempArray[0]);
            this.PageIndex = int.Parse(tempArray[1]);
            this.SortColumn = tempArray[2];
            this.SortOrder = tempArray[3];
        }

        /// <summary>
        /// Build a string used to cache the current GridSettings object.
        /// </summary>
        /// <returns>A string that represents the current GridSettings object.</returns>
        public override string ToString()
        {
            return string.Format("{0}#;{1}#;{2}#;{3}",
                this.PageSize,
                this.PageIndex,
                this.SortColumn,
                this.SortOrder);
        }

        /// <summary>
        /// Load the data from the data source for the current grid settings.
        /// </summary>
        /// <typeparam name="T">The entity type used as data model.</typeparam>
        /// <param name="dataSource">The data source.</param>
        /// <param name="count">Returns the number of elements of the returned results.</param>
        /// <returns>The grid data that match the current grid settings.</returns>
        public IQueryable<T> LoadGridData<T>(IQueryable<T> dataSource, out int count)
        {
            var query = dataSource;
            //
            // Sorting and Paging by using the current grid settings.
            //
            query = query.OrderBy<T>(this.SortColumn, this.SortOrder);
            count = query.Count();
            //
            if (this.PageIndex < 1)
                this.PageIndex = 1;
            //
            var data = query.Skip((this.PageIndex - 1) * this.PageSize).Take(this.PageSize);
            //
            return data;
        }
    }
}