给datagrid控件建立稳固的双向排序(asp.net)
大家都知道DataGrid控件带有内置的事件来对记录进行排序,用户可单击列标题，就会按照相应的列进行排序,使用
非常方便和简单化.
但是它也有很大的不足,就是由datagrid代理的分页功能，只能单向排序，而且换页后，排序信息就会丢失.所以我
们需要改进一下分页的事件函数,利用状态包ViewState变量,达到能稳固的双向排序。:)
(1)首先在页面load时.要读取数据源里的数据,并将其送入到DataGrid
private void page_load(Object obj,EventArgs e)
{
if(!Page.IsPostBack)
{
DataLoad();
}
}
private void DataLoad()
{
string connstr=ConfigurationSettings.AppSettings["ConnectionString"];
OleDbConnection conn=new OleDbConnection(connstr);
DataSet ds=new DataSet();
string sql;
if(ViewState["sorting"]==null)
{
sql="select * from userinfo";
Response.Write(sql);
}
else
{
sql="select * from userinfo order by "+ViewState["sorting"].ToString()+"
"+ViewState["sortdirection"].ToString();
Response.Write(sql);
}
OleDbDataAdapter da=new OleDbDataAdapter(sql,conn);
da.Fill(ds);
DataView dv=new DataView(ds.Tables[0]);
grid1.DataSource=dv;
grid1.DataBind();
}
(2)然后在datagrid控件的属性设定中加入如下选项;
...
allowpaging="true"
pagesize=13
pagerstyle-mode=numericpages
onpageindexchanged="changepage"
...
其中allowpaging="true",表示将启用分页功能,每页的大小，我们设定小一些(pagesize=13)，好让它多分页.
pagerstyle-mode=numericpages是将分页模式设为数字,最后指定了事件的处理程序为changepage方法.
private void changepage(Object obj,DataGridPageChangedEventArgs e)
{
grid1.CurrentPageIndex=e.NewPageIndex;//当前页等于新的页面
DataLoad();
}
(3)最后是排序的事件函数:
private void grid_sort(Object obj,DataGridSortCommandEventArgs e)
{
ViewState.Add("sorting",e.SortExpression);
if (ViewState["sortdirection"]==null)
ViewState.Add("sortdirection","ASC");
else
{
if(ViewState["sortdirection"].ToString()=="ASC")
ViewState["sortdirection"]="DESC";
else
ViewState["sortdirection"]="ASC";
}
DataLoad();
}
整个完整程序为:
< %@page language="C#"%>
< %@import namespace="System.Data"%>
< %@import namespace="System.Data.OleDb"%>
1<script language="c#" runat="server">
2
3private void page_load(Object obj,EventArgs e)
4{
5if(!Page.IsPostBack)
6{
7DataLoad();
8}
9}
10
11private void DataLoad()
12{
13string connstr=ConfigurationSettings.AppSettings["ConnectionString"];
14OleDbConnection conn=new OleDbConnection(connstr);
15DataSet ds=new DataSet();
16
17string sql;
18
19if(ViewState["sorting"]==null)
20{
21sql="select * from userinfo";
22Response.Write(sql);
23}
24else
25{
26sql="select * from userinfo order by "+ViewState["sorting"].ToString()+"
27
28"+ViewState["sortdirection"].ToString();
29Response.Write(sql);
30}
31
32OleDbDataAdapter da=new OleDbDataAdapter(sql,conn);
33da.Fill(ds);
34DataView dv=new DataView(ds.Tables[0]);
35grid1.DataSource=dv;
36grid1.DataBind();
37}
38
39
40private void changepage(Object obj,DataGridPageChangedEventArgs e)
41{
42grid1.CurrentPageIndex=e.NewPageIndex;//当前页等于新的页面
43DataLoad();
44}
45
46
47private void grid_sort(Object obj,DataGridSortCommandEventArgs e)
48{
49ViewState.Add("sorting",e.SortExpression);
50if (ViewState["sortdirection"]==null)
51ViewState.Add("sortdirection","ASC");
52else
53{
54if(ViewState["sortdirection"].ToString()=="ASC")
55ViewState["sortdirection"]="DESC";
56else
57ViewState["sortdirection"]="ASC";
58}
59DataLoad();
60}
61</script>
1<form runat="server">
2<asp:datagrid allowpaging="true" allowsorting="True" alternatingitemstyle-backcolor="#feeeee" autogeneratecolumns="false" bordercolor="#999999" font-size="10pt" headerstyle-backcolor="lightyellow" id="grid1" itemstyle-backcolor="#CCCCCC" onpageindexchanged="changepage" onsortcommand="grid_sort" pagerstyle-mode="numericpages" pagesize="13" runat="server">
3<columns>
4<asp:templatecolumn headertext="编号" sortexpression="id">
5<itemtemplate>
6<span>```
7#DataBinder.Eval(Container.DataItem,"id")
8```</span>
9</itemtemplate>
10</asp:templatecolumn>
11<asp:templatecolumn headertext="用户名" sortexpression="username">
12<itemtemplate>
13<span>```
14#DataBinder.Eval(Container.DataItem,"username")
15```</span>
16</itemtemplate>
17</asp:templatecolumn>
18<asp:templatecolumn headertext="电话" sortexpression="phone">
19<itemtemplate>
20<span>```
21#DataBinder.Eval(Container.DataItem,"phone")
22```</span>
23</itemtemplate>
24</asp:templatecolumn>
25<asp:templatecolumn headertext="ip地址" sortexpression="ip_address">
26<itemtemplate>
27<span>```
28#DataBinder.Eval(Container.DataItem,"ip_address")
29```</span>
30</itemtemplate>
31</asp:templatecolumn>
32</columns>
33</asp:datagrid>
34</form>