gridview

SqlConnection con;
    SqlCommand com;
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            ViewState["orderN"] = "ti";
            ViewState["orderT"] = "asc";
            bind();
        }
    }
    public void bind()
    {
        con = new SqlConnection("Data Source=.;Initial Catalog=tt;User ID=sa;Pwd=xxxx");
        con.Open();
        SqlDataAdapter da = new SqlDataAdapter("select id,ti,in,dy from tt",con);
        DataSet ds = new DataSet();
        da.Fill(ds,"tt");
        DataView view = ds.Tables["tt"].DefaultView;
        string sort = (string)ViewState["orderN"] + " " + (string)ViewState["orderT"];
        view.Sort = sort;
        GridView1.DataSource = view;
        GridView1.DataKeyNames = new string[] { "id"};
        GridView1.DataBind();
        con.Close();
    }


    protected void GridView1_RowDeleting(object sender, GridViewDeleteEventArgs e)
    {
        string id = GridView1.DataKeys[e.RowIndex].Value.ToString();
        con = new SqlConnection("Data Source=.;Initial Catalog=tt;User ID=sa;Pwd=xxxx");
        con.Open();
        com = new SqlCommand("delete t where id='"+id+"'",con);
        com.ExecuteNonQuery();
        con.Close();
        bind();
    }
    protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
    {
        GridView1.EditIndex = e.NewEditIndex;
        bind();
    }
    protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
        string ti= ((TextBox)(GridView1.Rows[e.RowIndex].Cells[1].Controls[0])).Text.Trim();
        string in = ((TextBox)(GridView1.Rows[e.RowIndex].Cells[2].Controls[0])).Text.Trim();
        string dy = ((TextBox)(GridView1.Rows[e.RowIndex].Cells[3].Controls[0])).Text.Trim();
        string id = GridView1.DataKeys[e.RowIndex].Value.ToString();
        con = new SqlConnection("Data Source=.;Initial Catalog=tt;User ID=sa;Pwd=xxxx");
        con.Open();
        string upsql = "update t set ti='" + ti + "',in='" + in + "',dy='" + dy + "' where id='"+id+"'";
        com = new SqlCommand(upsql,con);
        com.ExecuteNonQuery();
        con.Close();
        GridView1.EditIndex = -1;
        bind();
    }
   
    protected void GridView1_Sorting(object sender, GridViewSortEventArgs e)
    {
        string spage = e.SortExpression;
        if ((string)ViewState["orderN"] == spage)
        {
            if ((string)ViewState["orderT"] == "asc")
            {
                ViewState["orderT"] = "desc";
            }
            else
            {
                ViewState["orderT"] = "asc";
            }
        }
        else {
            ViewState["orderN"] = spage;
        }
        bind();
    }
    protected void GridView1_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
    {
        GridView1.EditIndex = -1;
        bind();
    }
    protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        for (int i = 0; i < GridView1.Rows.Count; i++)
        {
            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                e.Row.Attributes.Add("onmouseover", "c=this.style.backgroundColor;this.style.backgroundColor='red'");
                e.Row.Attributes.Add("onmouseout", "this.style.backgroundColor=c");
            }
        }
    }
    protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
    {
        GridView1.PageIndex = e.NewPageIndex;
        bind();
    }

  <asp:GridView ID="GridView1" runat="server" AllowPaging="True" 
            AllowSorting="True" AutoGenerateColumns="False" 
            onrowcancelingedit="GridView1_RowCancelingEdit" 
            onrowdeleting="GridView1_RowDeleting" onrowediting="GridView1_RowEditing" 
            onrowupdating="GridView1_RowUpdating" 
            onsorting="GridView1_Sorting" CellPadding="4" ForeColor="#333333" 
            GridLines="None" Width="80%" onrowdatabound="GridView1_RowDataBound" 
            onpageindexchanging="GridView1_PageIndexChanging">
            <RowStyle BackColor="#F7F6F3" ForeColor="#333333" />
            <Columns>
                <asp:BoundField DataField="id" HeaderText="id" Visible="False" />
                <asp:BoundField DataField="ti" SortExpression="ti" HeaderText="aa" />
                <asp:BoundField DataField="in" SortExpression="in" HeaderText="bbb" />
                <asp:BoundField DataField="dy" SortExpression="dy" HeaderText="cc" />
                <asp:CommandField  ShowEditButton="True"/>
                <asp:TemplateField ShowHeader="False">
                    <ItemTemplate>
                        <asp:LinkButton ID="LinkButton1" runat="server" CausesValidation="False" OnClientClick="javascript:return confirm('是否确定要删除本记录？')" 
                            CommandName="Delete" Text="删除"></asp:LinkButton>
                    </ItemTemplate>
                </asp:TemplateField>
            </Columns>
            <FooterStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
            <PagerStyle BackColor="#284775" ForeColor="White" HorizontalAlign="Center" />
            <SelectedRowStyle BackColor="#E2DED6" Font-Bold="True" ForeColor="#333333" />
            <HeaderStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
            <EditRowStyle BackColor="#999999" />
            <AlternatingRowStyle BackColor="White" ForeColor="#284775" />
        </asp:GridView>