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"%>
<script language="c#" runat="server">
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();
}
private void changepage(Object obj,DataGridPageChangedEventArgs e)
{
grid1.CurrentPageIndex=e.NewPageIndex;//当前页等于新的页面
DataLoad();
}
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();
}
</script>
<form runat="server">
<asp:datagrid id="grid1" runat="server"
alternatingitemstyle-backcolor="#feeeee"
ItemStyle-BackColor="#CCCCCC"
AutoGenerateColumns="false"
headerstyle-backcolor="lightyellow"
font-size="10pt"
bordercolor="#999999"
allowpaging="true"
pagesize=13
pagerstyle-mode=numericpages
onpageindexchanged="changepage"
AllowSorting="True"
onsortcommand="grid_sort"
>
<columns>
<asp:templatecolumn headertext="编号" SortExpression="id">
<itemtemplate>
<span><%#DataBinder.Eval(Container.DataItem,"id")%></span>
</itemtemplate>
</asp:templatecolumn>
<asp:TemplateColumn HeaderText="用户名" SortExpression="username">
<ItemTemplate>
<span><%#DataBinder.Eval(Container.DataItem,"username")%></span>
</ItemTemplate>
</asp:TemplateColumn>
<asp:templatecolumn headertext="电话" SortExpression="phone">
<itemtemplate>
<span><%#DataBinder.Eval(Container.DataItem,"phone")%></span>
</itemtemplate>
</asp:templatecolumn>
<asp:templatecolumn headertext="ip地址" SortExpression="ip_address">
<itemtemplate>
<span><%#DataBinder.Eval(Container.DataItem,"ip_address")%></span>
</itemtemplate>
</asp:templatecolumn>
</columns>
</asp:datagrid>
</form>
