Gridview - Multi-column sorting

Question

Hi.
I am using VS 2017 and ASP.NET C# website. I am trying to achieve multi column sorting in Gridview ? I have added allowsorting to true and added sortexpression on all BoundField columns. However, the sorting does not work on multiple columns. Below is the code used . How to fix this?

  
                                                     
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Answer

You have to use the data source control with the GridView such as the SqlDataSource and ObjectDataSoure to enable sorting.

Otherwise you will have to write the code to enable sorting by yourself. Shown blow is sample:

.aspx.cs

using System;  
using System.Collections.Generic;  
using System.Linq;  
using System.Web;  
using System.Web.UI;  
using System.Web.UI.WebControls;  
using System.Data;  
   
public partial class _0055_GridViewSorting : System.Web.UI.Page  
{  
    // Create DataView as data source of GridView  
    protected DataView CreateDataSource()  
    {  
        DataTable dt = new DataTable();  
        DataRow dr;  
   
        dt.Columns.Add(new DataColumn("ID", typeof(Int32)));  
        dt.Columns.Add(new DataColumn("Name", typeof(string)));  
        dt.Columns.Add(new DataColumn("Type", typeof(string)));  
        dt.Columns.Add(new DataColumn("Price", typeof(Int32)));  
        dt.Columns.Add(new DataColumn("Qty", typeof(Int32)));  
        dt.Columns.Add(new DataColumn("Amount", typeof(Int32)));  
        dt.Columns.Add(new DataColumn("CatID", typeof(Int32)));  
        dt.Columns.Add(new DataColumn("Note", typeof(string)));  
        dt.Columns.Add(new DataColumn("Disc", typeof(bool)));  
        dt.Columns.Add(new DataColumn("Date", typeof(DateTime)));  
   
        for (int i = 0; i < 15; i++)  
        {  
            dr = dt.NewRow();  
            dr["ID"] = i;  
            dr["Name"] = "Product Name_" + i.ToString();  
            dr["Type"] = "Product Type " + (100 - i).ToString();  
            dr["Price"] = 123000 * (i + 1);  
            dr["Qty"] = (i + 1) * 20;  
            dr["Amount"] = 123000 * (i + 1) * (i + 1);  
            dr["CatID"] = 100 - i;  
            dr["Note"] = "Note_" + i.ToString();  
            dr["Disc"] = (i % 2 == 0) ? true : false;  
            dr["Date"] = DateTime.Now.AddDays(i);  
            dt.Rows.Add(dr);  
        }  
        return new DataView(dt);  
    }  
   
    protected void Page_Load(object sender, EventArgs e)  
    {  
        if (!Page.IsPostBack)  
        {  
            GridView1.DataSource = CreateDataSource();  
            GridView1.DataBind();  
        }  
    }  
   
    protected void GridView1_Sorting(object sender,   
                                      GridViewSortEventArgs e)  
    {  
        GridView gv = (GridView)sender;  
        DataView view = CreateDataSource();  
        string exp = e.SortExpression;  
   
        // switch ASC / DESC when same LinkButton is clicked  
        if (gv.Attributes["CurrentSortField"] != null &&  
            gv.Attributes["CurrentSortDir"] != null)  
        {  
            if (exp == gv.Attributes["CurrentSortField"])  
            {  
                if (gv.Attributes["CurrentSortDir"] == "ASC")  
                {  
                    exp = exp + " DESC";  
                    gv.Attributes["CurrentSortDir"] = "DESC";  
                }  
                else  
                {  
                    exp = exp + " ASC";  
                    gv.Attributes["CurrentSortDir"] = "ASC";  
                }  
            }  
            else  
            {  
                gv.Attributes["CurrentSortField"] = exp;  
                exp = exp + " ASC";  
                gv.Attributes["CurrentSortDir"] = "ASC";  
            }  
        }  
   
        view.Sort = exp;  
        gv.DataSource = view;  
        gv.DataBind();  
    }  
}

.aspx

<%@ Page Language="C#" AutoEventWireup="true"   
    CodeFile="0055-GridViewSorting.aspx.cs"   
    Inherits="_0055_GridViewSorting" %>

Result

Answer

Hi @venkatesh padmanabhan ,
You need to use gridView.Sorting Event：Occurs when the hyperlink to sort a column is clicked, but before the GridView control handles the sort operation.
https://learn.microsoft.com/en-us/dotnet/api/system.web.ui.webcontrols.gridview.sorting?view=netframework-4.8
You can refer to the example in the official documentation.

protected void TaskGridView_Sorting(object sender, GridViewSortEventArgs e)  
  {  
  
    //Retrieve the table from the session object.  
    DataTable dt = Session["TaskTable"] as DataTable;  
  
    if (dt != null)  
    {  
  
      //Sort the data.  
      dt.DefaultView.Sort = e.SortExpression + " " + GetSortDirection(e.SortExpression);  
      TaskGridView.DataSource = Session["TaskTable"];  
      TaskGridView.DataBind();  
    }  
  
  }  
  
  private string GetSortDirection(string column)  
  {  
  
    // By default, set the sort direction to ascending.  
    string sortDirection = "ASC";  
  
    // Retrieve the last column that was sorted.  
    string sortExpression = ViewState["SortExpression"] as string;  
  
    if (sortExpression != null)  
    {  
      // Check if the same column is being sorted.  
      // Otherwise, the default value can be returned.  
      if (sortExpression == column)  
      {  
        string lastDirection = ViewState["SortDirection"] as string;  
        if ((lastDirection != null) && (lastDirection == "ASC"))  
        {  
          sortDirection = "DESC";  
        }  
      }  
    }  
  
    // Save new values in ViewState.  
    ViewState["SortDirection"] = sortDirection;  
    ViewState["SortExpression"] = column;  
  
    return sortDirection;  
  }

Best regards,
Lan Huang

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Gridview - Multi-column sorting

2 answers