<asp:GridView ID="GridView1" runat="server" AllowPaging="True" 
            AutoGenerateColumns="False" AutoGenerateDeleteButton="True" 
            AutoGenerateEditButton="True" 
            onrowdeleting="GridView1_RowDeleting" onrowediting="GridView1_RowEditing" 
            onrowupdating="GridView1_RowUpdating" OnRowCancelingEdit="GridView1_RowCancelingEdit"  
           PageSize="3" onpageindexchanging="GridView1_PageIndexChanging"> 
            <Columns> 
                
               
                 <asp:TemplateField HeaderText="EmployeeNo"> 
                <ItemTemplate> 
                <%#Eval("EmployeeNo")%> 
                </ItemTemplate> 
                <EditItemTemplate > 
                <asp:TextBox ID="txtEmployeeNo" runat="server" Text=' <%#Eval("EmployeeNo")%> '> </asp:TextBox> 
                </EditItemTemplate> 
                </asp:TemplateField> 
                
                <asp:TemplateField HeaderText="Name"> 
                <ItemTemplate> 
                <%#Eval("Name")%> 
                </ItemTemplate> 
                <EditItemTemplate > 
                <asp:TextBox ID="txtName" runat="server" Text=' <%#Eval("Name")%> '> </asp:TextBox> 
                </EditItemTemplate> 
                </asp:TemplateField> 
                
                 <asp:TemplateField HeaderText="Email"> 
                <ItemTemplate> 
                <%#Eval("Email")%> 
                </ItemTemplate> 
                <EditItemTemplate > 
                <asp:TextBox ID="txtEmail" runat="server" Text=' <%#Eval("Email")%> '> </asp:TextBox> 
                </EditItemTemplate> 
                </asp:TemplateField> 
                
                
            </Columns> 
        </asp:GridView> 

public partial class GridOperations : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if(!IsPostBack)
         //Bind the GridView from database
            bind();
    }
    protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
    {
       //point to current index
        GridView1.EditIndex = e.NewEditIndex; 
         //Bind the GrisView from database
        bind();

    }
    protected void GridView1_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
    { 
        GridView1.EditIndex = -1; 
         //Bind the GridView from database
        bind(); 
    }   
    protected void GridView1_RowDeleting(object sender, GridViewDeleteEventArgs e)
    {
       //Row delete 
        GridViewRow row = (GridViewRow)GridView1.Rows[e.RowIndex];
        TextBox email = (TextBox)row.FindControl("txtEmail");
        SqlConnection conn = new SqlConnection("Data Source=localhost;Initial Catalog=Db;Integrated Security=True");
        conn.Open();
        SqlCommand cmd = new SqlCommand("delete from  tab1 where Email='" + email.Text + "'", conn);
        cmd.ExecuteNonQuery();
        conn.Close();
        bind();

    }
    protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
        GridViewRow row = (GridViewRow)GridView1.Rows[e.RowIndex]; 
        TextBox name=  (TextBox)row.FindControl("txtName");
        TextBox empno = (TextBox)row.FindControl("txtEmployeeNo");
        TextBox email = (TextBox)row.FindControl("txtEmail");
        GridView1.EditIndex = -1;
        SqlConnection conn = new SqlConnection("Data Source=localhost;Initial Catalog=Db;Integrated Security=True");
        conn.Open();
        SqlCommand cmd = new SqlCommand("update  tab1 set Name='" + name.Text + " ',Email='" + email.Text + "' where EmployeeNo='" + empno.Text + "'", conn);
        cmd.ExecuteNonQuery(); 
        conn.Close();
        bind();

    }
 //Bind the GrisView from database

    public void bind()
    {
        SqlConnection conn = new SqlConnection("Data Source=localhost;Initial Catalog=Db;Integrated Security=True");
        conn.Open();
        SqlDataAdapter da = new SqlDataAdapter("select EmployeeNo,Name,Email from tab1", conn);
        DataSet ds = new DataSet();
        da.Fill(ds, "emp"); 
        GridView1.DataSource = ds.Tables[0];
        GridView1.DataBind();
        conn.Close();
    }
    protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
    {
        GridView1.PageIndex = e.NewPageIndex;
        bind();
    }
}