Gridview：捕獲排序方向

Question

我在啟用了排序的updatepanel中有一個gridview，並且有一個事件處理程序，如下所示：

protected void MyGridSort(object sender, GridViewSortEventArgs e)
{
   var TheDirection = (e.SortDirection).ToString();
   var TheColumn = (e.SortExpression).ToString();
}

我在這些行之后放置一個斷點。 每次按下列標題時，變量TheDirection總是顯示升序。

為什么不從上升切換到下降然后返回？

謝謝。

Answer 1

我一直在閱讀，當您手動向gridview提供數據源時，排序似乎中斷了。 不確定是否是您的情況，但這對我有用。

string strSortExpression = e.SortExpression + " ASC";
if (Convert.ToString(ViewState["SortExpression"]) == strSortExpression)
{
    strSortExpression = e.SortExpression + " DESC";
}
ViewState["SortExpression"] = strSortExpression;


//This is done by sorting the Default View of the underlying data and then re-binding this
//to the grid.
System.Data.DataTable myData = HttpContext.Current.Session["GridData"] as System.Data.DataTable;
if (myData != null)
{
   myData.DefaultView.Sort = strSortExpression;
   GridView1.DataSource = myData;
   GridView1.DataBind();
}

希望能幫助到你

Answer 2

您可以將方向保持在ViewState或Session中。 像這樣（未經測試的代碼）：

protected void MyGridSort(object sender, GridViewSortEventArgs e)
{
   var TheDirection = (e.SortDirection).ToString();
   var TheColumn = (e.SortExpression).ToString();

   string prevColumn = "", prevDirection = "";

   if (Session["MyGridSortColumn"] != null)
      prevColumn = Session["MyGridSortColumn"].ToString();
   if (Session["MyGridSortDirection"] != null)
      prevDirection = Session["MyGridSortDirection"].ToString();

   if (TheColumn == prevColumn) {
      if (prevDirection == "ASC")
         TheDirection = "DESC";
      else
         TheDirection = "ASC";
   }

   Session["MyGridSortDirection"] = TheDirection;
   Session["MyGridSortColumn"] = TheColumn;

}