ASP.Net 翻页后继续维持排序

要想实现翻页后继续排序,实现这样的效果:
比如共 15笔记录，每页显示10条
则排序时:第一页将前10条记录排序，翻第二页时后五条再单独排序.

要注意以下几点:
1.如果数据很多,最好不要把数据集放到缓存中(viewstate),影响性能

2. ViewState中存放上次是哪个e.expression并且存放此e.expression是升序还是降序

示例如下:
1.现有的排序事件是这样写的,这个是点击上面排序标题时用:
  private void grdProjTrace_SortCommand(object source, DataGridSortCommandEventArgs e)
{
 this.grdProjTrace.CurrentPageIndex = 0;
 DataView dv = 得到数据代码;
 string strSort = "";
 string strOrder ="";//排序方式。0，降序，1升序
 if(ViewState["SortExpresstion"] != null)
 {
  strSort = ViewState["SortExpresstion"].ToString();
  strSort = strSort.Substring(0,strSort.Length -1);
  strOrder = ViewState["SortExpresstion"].ToString();
  strOrder = strOrder.Substring(strOrder.Length -1);
 }
 if(e.SortExpression == "CustomerName")
 {
  if(strSort != "CustomerName")
  {
   this.ViewState["SortExpresstion"] = ustomerName0";
   dv.Sort = "CustomerName DESC";
  }
  else
  {
   if(strOrder == "0")
   {
    this.ViewState["SortExpresstion"] = "CustomerName1";
    dv.Sort = "CustomerName ASC";
   }
   else
   {
    this.ViewState["SortExpresstion"] = "CustomerName0";
    dv.Sort = "CustomerName DESC";
   }
  }
 }
if(e.SortExpression == "fullName")
 {
  if(strSort != "fullName")
  {
   this.ViewState["SortExpresstion"] = "fullName0";
   dv.Sort = "fullName DESC";
  }
  else
  {
   if(strOrder == "0")
   {
    this.ViewState["SortExpresstion"] = "fullName1";
    dv.Sort = "fullName ASC";
   }
   else
   {
    this.ViewState["SortExpresstion"] = "fullName0";
    dv.Sort = "fullName DESC";
   }
  }
 }   
        this.grdProjTrace.DataSource = dv;
 this.grdProjTrace.DataBind();
}

2.下面这个方法是自己写的，翻页事件中调用。
private void ChangePageDataBind()  
{
 DataView dv = 得到数据代码;
 string strSort = "";
 string strOrder ="";//排序方式。0，降序，1升序
 if(ViewState["SortExpresstion"] != null)
 {
  strSort = ViewState["SortExpresstion"].ToString();
  strSort = strSort.Substring(0,strSort.Length -1);
  strOrder = ViewState["SortExpresstion"].ToString();
  strOrder = strOrder.Substring(strOrder.Length -1);
 }
 if(this.ViewState["SortExpresstion"] != null)
 {    
  if(strSort == "CustomerName")
  {
   if(strOrder == "1")
   {
    this.ViewState["SortExpresstion"] = "CustomerName1";
    dv.Sort = "CustomerName ASC";
   }
   else
   {
    this.ViewState["SortExpresstion"] = "CustomerName0";
    dv.Sort = "CustomerName DESC";
   }
  }
 }
 if(this.ViewState["SortExpresstion"] != null)
 {    
  if(strSort == "fullName")
  {
   if(strOrder == "1")
   {
    this.ViewState["SortExpresstion"] = "fullName1";
    dv.Sort = "fullName ASC";
   }
   else
   {
    this.ViewState["SortExpresstion"] = "fullName0";
    dv.Sort = "fullName DESC";
   }
  }
 }   
this.grdProjTrace.DataSource = dv;
this.grdProjTrace.DataBind();
}

上面两方法只要修改要排序的字段名，就可以直接调用了.
1方法很简单使用,这里就不说了.
2方法是这样用的:
private void grdProjTrace_PageIndexChanged(object source, DataGridPageChangedEventArgs e)
{
 try
 {    
  try
  {
     this.grdProjTrace.CurrentPageIndex = e.NewPageIndex;
  }
  catch
  {
   this.grdProjTrace.CurrentPageIndex = 0;
  }

  
  this.ChangePageDataBind();
 }
 catch(System.Exception errWS)
 {  
         //异常
 }
}