How to solve this error:the gridview 'gridview1' fired event rowediting which wasn't handled.

            using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;

namespace EmpGrid
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        static DataTable ds = new DataTable();
        private SqlConnection conn = new SqlConnection(@"Data Source=ADMIN-PC\SQLEXPRESS;Initial Catalog=task;User ID=sa;Password=ups");  

        protected void Page_Load(object sender, EventArgs e)
        {
            if (!this.IsPostBack)
            {
                if (!ds.Columns.Contains("id"))
                    
                          
                   

                ds.Columns.Add("id");
                if (!ds.Columns.Contains("name"))
                ds.Columns.Add("name");
                if (!ds.Columns.Contains("salary"))
                ds.Columns.Add("salary");

             
                // GridView1.DataSource = dt;
                // GridView1.DataBind();

                gvbind();

            }
            }
            protected void gvbind() {  
        conn.Open();
        SqlCommand cmd = new SqlCommand("Select * from empdet", conn);  
        SqlDataAdapter da = new SqlDataAdapter(cmd);  
        DataSet ds = new DataSet();  
        da.Fill(ds);  
        conn.Close();  
        if (ds.Tables[0].Rows.Count > 0) {  
            GridView1.DataSource = ds;  
            GridView1.DataBind();  
        } else {  
            //ds.Tables[0].Rows.Add(ds.Tables[0].NewRow());
            GridView1.DataSource = new String[] { };
            GridView1.DataBind();  
            
          
        }  
        }

            protected void GridView1_RowDeleting(object sender, GridViewDeleteEventArgs e)
            {
                GridViewRow row = (GridViewRow)GridView1.Rows[e.RowIndex];
                Label lbldeleteid = (Label)row.FindControl("lblID");
                conn.Open();
                SqlCommand cmd = new SqlCommand("delete FROM empdet where id='" + Convert.ToInt32(GridView1.DataKeys[e.RowIndex].Value.ToString()) + "'", conn);
                cmd.ExecuteNonQuery();
                conn.Close();
                gvbind();
            }

            protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
            {

                GridView1.EditIndex = e.NewEditIndex;
                gvbind();
            }
            protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
            {
                int id = Convert.ToInt32(GridView1.DataKeys[e.RowIndex].Value);

                GridViewRow row = (GridViewRow)GridView1.Rows[e.RowIndex];
                Label lblID = (Label)row.FindControl("lblID");

                TextBox textName = (TextBox)row.Cells[0].Controls[0];
                TextBox textadd = (TextBox)row.Cells[1].Controls[0];
               // TextBox textc = (TextBox)row.Cells[2].Controls[0];



                GridView1.EditIndex = -1;
                GridView1.DataBind();
                conn.Open();

                SqlCommand cmd = new SqlCommand("update empdet set name='" + textName.Text + "',salary='" + textadd.Text + "'where id='" + id + "'", conn);


                cmd.ExecuteNonQuery();

                conn.Close();
                gvbind();
            }

            protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
            {
                GridView1.PageIndex = e.NewPageIndex;
                gvbind();
            }
            protected void GridView1_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
            {
                GridView1.EditIndex = -1;
                gvbind();



            }

        protected void Add_Click(object sender, EventArgs e)
        {
            GridView1.Visible = true;
            //createnewrow();
            ds.Rows.Add(TextBox1.Text, TextBox2.Text, TextBox3.Text);

            TextBox1.Text = "";
            TextBox2.Text = "";
            TextBox3.Text = "";

            GridView1.DataSource = ds;
            GridView1.DataBind();
            GridView1.DataSource = null;

        }

        protected void Save_Click(object sender, EventArgs e)
        {
            //   foreach (DataGridViewRow row in GridView1.Rows)
            for (int i = 0; i < GridView1.Rows.Count; i++)
            {
                string constring = @"Data Source=ADMIN-PC\SQLEXPRESS;Initial Catalog=task;User ID=sa;Password=ups";
                using (SqlConnection con = new SqlConnection(constring))
                {
                    using (SqlCommand cmd = new SqlCommand("INSERT INTO empdet VALUES( @id,NEWID(),@name, @salary,getdate())", con))
                    {
                        cmd.Parameters.AddWithValue("@id", GridView1.Rows[i].Cells[0].Text);
                        cmd.Parameters.AddWithValue("@name", GridView1.Rows[i].Cells[1].Text);
                        cmd.Parameters.AddWithValue("@salary", GridView1.Rows[i].Cells[2].Text);
                        //cmd.Parameters.AddWithValue("@Name", row.Cells["Name"].Value);
                        //cmd.Parameters.AddWithValue("@Address", row.Cells["Address"].Value);
                        con.Open();
                        cmd.ExecuteNonQuery();
                        con.Close();
                    }
                }


            }
        }
    }
}