执行搜索后的网格视图排序和分页

Question

我正在GridView中执行搜索操作并按预期方式获得结果，但是在获得结果后，如果对它们进行排序或单击分页，则会重新加载页面，并且整个网格都将发生排序和分页。应该只能用于我得到的搜索结果。

protected void Page_Load(object sender, EventArgs e)
{       
    if (!IsPostBack)
    {
        bindgrid();           
    }
}

protected void bindgrid()
{
    ViewState["sortexp"] = "";
    ViewState["orderby"] = "ASC";
    Sort("");
    int iTotalRecords = ((DataTable)(GridView1.DataSource)).Rows.Count;
    lbldisplay.Text = "Total Products: " + iTotalRecords.ToString();
}
protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
    GridView1.PageIndex = e.NewPageIndex;
    GridView1.DataBind();
    Panel2.Visible = true;
    bindgrid();
}
public void Sort(string sortexp)
{
    DataTable dt = (DataTable)bll.LoadProduct();
    DataView DV = dt.DefaultView;
    if (sortexp != "")
    {
        DV.Sort = sortexp;
    }
    GridView1.DataSource = DV;
    GridView1.DataBind();
}
protected void GridView1_Sorting(object sender, GridViewSortEventArgs e)
{
    if (ViewState["orderby"].ToString() == "ASC")
    {
        ViewState["orderby"] = "DESC";
        ViewState["sortexp"] = e.SortExpression + " " + " DESC";
    }
    else
    {
        ViewState["orderby"] = "ASC";
        ViewState["sortexp"] = e.SortExpression + " " + " ASC";
    }
    Sort(ViewState["sortexp"].ToString());
}