GridView

protected void Page_Load(object sender, EventArgs e)
    {
        if(!IsPostBack)
        {
            DataBindUser();
        }
    }
    private DataSet DataBindUser()
    {
        SqlConnection cn = new SqlConnection(ConfigurationManager.ConnectionStrings["Net"].ConnectionString);
        SqlDataAdapter sda = new SqlDataAdapter("select * from users",cn);
        DataSet ds = new DataSet();
        sda.Fill(ds);
        GridView1.DataSource = ds;
        GridView1.DataBind();
        return ds;
    }
    protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
    {
        GridView1.EditIndex = e.NewEditIndex;
        DataBindUser();
    }
    protected void GridView1_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
    {
        GridView1.EditIndex = -1;
        DataBindUser();
    }
    protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
        string id = GridView1.DataKeys[e.RowIndex].Value.ToString();
        string name = ((TextBox)GridView1.Rows[e.RowIndex].FindControl("txtName")).Text;
        User user = new User();
        user.UpdateUserName(id,name);
        DataBindUser();
    }
    protected void GridView1_RowDeleting(object sender, GridViewDeleteEventArgs e)
    {
        int id =Convert.ToInt16(GridView1.DataKeys[e.RowIndex].Value);
        User user = new User();
        user.DeleteUser(id);
        DataBindUser();
    }
    protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
    {
        GridView1.PageIndex = e.NewPageIndex;
        DataBindUser();
    }
    protected void GridView1_Sorting(object sender, GridViewSortEventArgs e)
    {
        string sortExpression = e.SortExpression;
        if (GridViewSortDirection == SortDirection.Ascending)
        {
            GridViewSortDirection = SortDirection.Descending;
            SortGridView(sortExpression, "ASC");
        }
        else
        {
            GridViewSortDirection = SortDirection.Ascending;
            SortGridView(sortExpression, "DESC");
        }
    }
    public SortDirection GridViewSortDirection
    {
        get
        {
            if (ViewState["sortDirection"] == null)
                ViewState["sortDirection"] = SortDirection.Ascending;
            return (SortDirection)ViewState["sortDirection"];
        }
        set
        {
            ViewState["sortDirection"] = value;
        }
    }
    private void SortGridView(string sortExpression, string direction)
    {
        DataTable dt = DataBindUser().Tables[0];
        DataView dv = new DataView(dt);
        dv.Sort = sortExpression + " " + direction;
        GridView1.DataSource = dv;
        GridView1.DataBind();
    }
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" OnRowCancelingEdit="GridView1_RowCancelingEdit" OnRowEditing="GridView1_RowEditing" DataKeyNames="userid" OnRowUpdating="GridView1_RowUpdating" OnRowDeleting="GridView1_RowDeleting" AllowPaging="True" OnPageIndexChanging="GridView1_PageIndexChanging" OnSorting="GridView1_Sorting" PageSize="3" AllowSorting="True">
            <Columns>
                <asp:TemplateField HeaderText="用戶" SortExpression="userName">
                    <ItemTemplate>
                        <asp:Label ID="lblname" runat="server" Text='<%# DataBinder.Eval(Container.DataItem,"userName")%>'></asp:Label>
                    </ItemTemplate>
                    <EditItemTemplate>
                        <asp:TextBox ID="txtname" runat="server" Text='<%# DataBinder.Eval(Container.DataItem,"userName")%>'></asp:TextBox>
                    </EditItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="操作">
                    <EditItemTemplate>
                        <asp:LinkButton ID="LinkButton1" runat="server" CommandName="update">更新</asp:LinkButton>
                        <asp:LinkButton ID="LinkButton2" runat="server" CommandName="cancel">取消</asp:LinkButton>
                    </EditItemTemplate>
                    <ItemTemplate>
                        <asp:LinkButton ID="LinkButton1" runat="server" CommandName="edit">編輯</asp:LinkButton>
                        <asp:LinkButton ID="LinkButton2" runat="server" CommandName="delete">刪除</asp:LinkButton>
                    </ItemTemplate>
                </asp:TemplateField>
            </Columns>
        </asp:GridView>