Calculate total price on Textbox change event

Step 3 : Apply code on page.cs part.

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;

protected void Page_Load(object sender, EventArgs e)
{
GridView1.DataSource = GetData();
GridView1.DataBind();
}
public DataSet GetData()
{
DataSet ds = new DataSet();
DataTable dt = new DataTable("Product");
DataRow dr;
dt.Columns.Add(new DataColumn("Price", typeof(Int32)));
dt.Columns.Add(new DataColumn("Qut", typeof(Int32)));
dt.Columns.Add(new DataColumn("TotalPrice", typeof(Int32)));
for (int i = 1; i <= 10; i++)
{
dr = dt.NewRow();
dr[0] = (20 * i);
dt.Rows.Add(dr);
}
ds.Tables.Add(dt);
Session["dt"] = dt;
return ds;
}
protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
Label lblCurrentListPrice = (Label)e.Row.FindControl("lblCurrentListPrice");
Double CurPr = Convert.ToDouble(lblCurrentListPrice.Text);
TextBox txtqut = (TextBox)e.Row.FindControl("txtqut");
Label lblTotal = (Label)e.Row.FindControl("lblTotal");
txtqut.Attributes.Add("onkeyup", "CalcSellPrice2(" + CurPr + ", '" + txtqut.ClientID + "','" + lblTotal.ClientID + "')");
}
}

Step 4 : Run page and getting out put thanks.