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ASP.NET: How to sort a GridView bound to a generic List

Posted on 2009-07-03
6
Medium Priority
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Last Modified: 2013-12-17
Hi all,

I have a gridview that I bind to a generic list in memory. I would like to know how I can sort that the gridview depending on the column clicked.
using System;
using System.Collections.Generic;
using System.Text;
 
namespace testList
{
    public class TestElement 
    {
        
        private int _id = null;
 
        private String _name = null;
 
        private int _age = null;
 
        private decimal _salary = null;
 
        private int _reportTo = null;
 
 
        public int Id
        {
            get { return _id; }
            set { _id = value; }
        }
 
        public String Name
        {
            get { return _name; }
            set { _name = value; }
        }
 
        public int Age
        {
            get { return _age; }
            set { _age = value; }
        }
 
        public decimal Salary
        {
            get { return _salary; }
            set { _salary = value; }
        }
 
        public int ReportTo
        {
            get { return _reportTo; }
            set { _reportTo = value; }
        }
 
    }
}
 
 
 
 
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Collections.Generic;
using System.Threading;
using testList;
 
public partial class testPage : Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            GridView grid = new GridView;
            List<TestElement> source = //Get the list
            grid.DataSource=source;
            grid.DataBind();
            
            Page.Controls.Add(grid);
        }
    }
}

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Question by:karakav
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6 Comments
 
LVL 9

Expert Comment

by:Rahul Goel ITIL
ID: 24771264
0
 
LVL 20

Accepted Solution

by:
ddayx10 earned 2000 total points
ID: 24771402
Well shucks. Here's a sample that does just that :)

I changed your object around a bit to fit my dev database, and simplified it for my convenience. It should give you the full picture of how to answer your question and it's pretty darn close to your code.

For the sorting, this should likely be implemented into your class more fully, but that is a large task and this works just fine for what you gave me to start with.

Check it out.

PS: Also threw in some new 3.5 property techniques you can check out...
****ASPX CODE****
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default28.aspx.cs" Inherits="Pages1_Default28" %>
 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
 
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
		<asp:GridView ID="gv" runat="server" AllowSorting="true" 
			AutoGenerateColumns="false" OnSorting="gv_Sorting">
			<Columns>
				<asp:BoundField HeaderText="ID" DataField="ID" SortExpression="ID" />
				<asp:BoundField HeaderText="Fname" DataField="fName" SortExpression="fName" />
				<asp:BoundField HeaderText="Lname" DataField="lName" SortExpression="lName" />
				<asp:BoundField HeaderText="Nname" DataField="nName" SortExpression="nName"/>
			</Columns>
		</asp:GridView>
    </form>
</body>
</html>
 
 
****CODE BEHIND****
 
using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Collections.Generic;
using System.Data.SqlClient;
 
public partial class Pages1_Default28 : System.Web.UI.Page
{
    public string connStr
    {
        get{ return ConfigurationManager.ConnectionStrings["conn"].ToString(); }
    }
 
 
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            bindData();
            ViewState["_lastSortDirection"] = "DESC";
        }
    }
 
 
 
 
    private void bindData()
    {
        List<TestElement> dSource = new List<TestElement>();
 
        SqlConnection conn = new SqlConnection(connStr);
        SqlCommand cmd = new SqlCommand("SELECT * FROM DevTable", conn);
        conn.Open();
        SqlDataReader dr = cmd.ExecuteReader();
        while(dr.Read())
        {
            TestElement ts = new TestElement();
            ts.Id = Convert.ToInt32(dr["testID"]);
            ts.fName = dr["fName"].ToString();
            ts.lName = dr["lName"].ToString();
            ts.nName = dr["nName"].ToString();
            dSource.Add(ts);
        }
        dr.Close();
        conn.Close();
        conn.Dispose();
        Session["dSource"] = dSource;
        gv.DataSource = dSource;
        gv.DataBind();
    }
 
    protected void gv_Sorting(object sender, GridViewSortEventArgs e)
    {
        List<TestElement> dSource = (List<TestElement>)Session["dSource"];
        switch (e.SortExpression)
        {
            case "ID":
                if (lastSortDirection() == "ASC")
                {
                    dSource.Sort(delegate(TestElement p1, TestElement p2) { return p1.Id.CompareTo(p2.Id) * -1; });
                }
                else
                {
                    dSource.Sort(delegate(TestElement p1, TestElement p2) { return p1.Id.CompareTo(p2.Id); });
                }
                break;
            case "fName":
                if (lastSortDirection() == "ASC")
                {
                    dSource.Sort(delegate(TestElement p1, TestElement p2) { return p1.fName.CompareTo(p2.fName) * -1; });
                }
                else
                {
                    dSource.Sort(delegate(TestElement p1, TestElement p2) { return p1.fName.CompareTo(p2.fName); });
                }
                break;
            case "lName":
                if (lastSortDirection() == "ASC")
                {
                    dSource.Sort(delegate(TestElement p1, TestElement p2) { return p1.lName.CompareTo(p2.lName) * -1; });
                }
                else
                {
                    dSource.Sort(delegate(TestElement p1, TestElement p2) { return p1.lName.CompareTo(p2.lName); });
                }
                break;
            case "nName":
                if (lastSortDirection() == "ASC")
                {
                    dSource.Sort(delegate(TestElement p1, TestElement p2) { return p1.nName.CompareTo(p2.nName) * -1; });
                }
                else
                {
                    dSource.Sort(delegate(TestElement p1, TestElement p2) { return p1.nName.CompareTo(p2.nName); });
                }
                break;
        }
        gv.DataSource = dSource;
        gv.DataBind();
        Session["dSource"] = dSource;
    }
 
 
    private string lastSortDirection()
    {
        if (ViewState["_lastSortDirection"] == null || String.IsNullOrEmpty(ViewState["_lastSortDirection"].ToString()))
        {
            ViewState["_lastSortDirection"] = "DESC";
            return ViewState["_lastSortDirection"].ToString();
        }
        else
        {
            if (ViewState["_lastSortDirection"].ToString() == "DESC")
            {
                ViewState["_lastSortDirection"] = "ASC";
                return ViewState["_lastSortDirection"].ToString();
            }
            else
            {
                ViewState["_lastSortDirection"] = "DESC";
                return ViewState["_lastSortDirection"].ToString();
            }
        }
    }
}
 
 
 
public class TestElement
{
 
    public int Id
    {
        get;
        set;
    }
 
    public String fName
    {
        get;
        set;
    }
 
    public String lName
    {
        get;
        set;
    }
 
    public String nName
    {
        get;
        set;
    }
}

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LVL 20

Expert Comment

by:ddayx10
ID: 24771404
No you other guys...this is the solution :) !!!!
0
 
LVL 20

Expert Comment

by:ddayx10
ID: 24771463
OK thought I'd look, that first one's by NNirmalan is not too bad (only not too bad cause I didn't do it that way, otherwise it's pretty cool)...

I sort the custom object properties, they convert the grid into a dataview and sort that :)

Pick yer poison...off for the weekend says I
0
 
LVL 4

Author Closing Comment

by:karakav
ID: 31599492
Thanks.
0

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