让Asp.NET的DataGrid可排序、可选择、可分页

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Asp.NETDataGrid可排序、可选择、可分页

       DataGridAsp.NET中的一个重要的控件,经常我们都将DataGrid做成可分页的和可排序的,有时还需要加上选择功能。这些都是经常需要用到的方法,其实是比较简单的。

 

设计思路:

为了方便起见,我们连接SQL Server 2000NorthWind数据库的Orders表,从数据库里得到此表的数据视图。利用DataGridSortCommand事件实现排序用一个模板列加上CheckBox控件实现选择。可用DataGrid的属性生成器的“分页”选项或者自己修改HTML实现分页。

 

HTML

  • 添加一个DataGrid,命名为dgOrder
  • 添加了一个模板列,模板列里放一个名为CbCheckBox控件。此列用来实现选择
  • 为要排序的每个列加上排序表达式SortExpression
  • 利用列的DataFormatString来格式化列,象DataFormatString="{0:d}"显示日期格式。
  • 设置PageSize="15"每页显示15行数据,AllowPaging="True" 为允许分页

 

整个HTML页代码:

<form id="Form1" method="post" runat="server">

       <asp:datagrid id="dgOrder" runat="server" Height="515px" Width="718px" AutoGenerateColumns="False" AllowSorting="True" CellPadding="4" BorderWidth="1px" BorderColor="#A0ABEB" PageSize="15" BorderStyle="Solid" BackColor="White" GridLines="Vertical" ForeColor="Black" AllowPaging="True" ShowFooter="True">

              <SelectedItemStyle ForeColor="White" BackColor="Black"></SelectedItemStyle>

              <AlternatingItemStyle BackColor="#EEEEEE"></AlternatingItemStyle>

              <HeaderStyle HorizontalAlign="Center" ForeColor="White" BorderColor="#6876C5" BackColor="#6876C5"></HeaderStyle>

              <FooterStyle ForeColor="White" BackColor="#6876C5"></FooterStyle>

              <Columns>

                     <asp:TemplateColumn>

                            <ItemTemplate>

                                   <FONT face="宋体">

                                          <asp:CheckBox id="Cb" runat="server"></asp:CheckBox></FONT>

                            </ItemTemplate>

                     </asp:TemplateColumn>

                     <asp:BoundColumn DataField="orderid" SortExpression="orderid" HeaderText="ID">

                            <HeaderStyle Width="180px"></HeaderStyle>

                     </asp:BoundColumn>

                     <asp:BoundColumn DataField="ShipCountry" SortExpression="ShipCountry" HeaderText="ShipCountry">

                            <HeaderStyle Width="180px"></HeaderStyle>

                     </asp:BoundColumn>

                     <asp:BoundColumn DataField="ShippedDate" SortExpression="ShippedDate" HeaderText="ShippedDate" DataFormatString="{0:d}">

                            <HeaderStyle Width="180px"></HeaderStyle>

                     </asp:BoundColumn>

                     <asp:BoundColumn DataField="Freight" SortExpression="Freight" HeaderText="Freight">

                            <HeaderStyle Width="180px"></HeaderStyle>

                     </asp:BoundColumn>

                     <asp:BoundColumn DataField="ShipAddress" SortExpression="ShipAddress" HeaderText="ShipAddress">

                            <HeaderStyle Width="480px"></HeaderStyle>

                     </asp:BoundColumn>

              </Columns>

              <PagerStyle HorizontalAlign="Center" ForeColor="Black" Position="TopAndBottom" BackColor="White" Mode="NumericPages"></PagerStyle>

       </asp:datagrid>

</form>

 

 

 

后台类添加以下代码:

 

Imports System.Data.SqlClient

 

'得到数据视图,参数为要排序的列

Private Function GetDv(ByVal strSort As String) As DataView

        '定义数据库连接

        Dim dv As DataView

        Dim CN As New SqlConnection()

        Try

            '初始化连接字符串

            CN.ConnectionString = "data source=pmserver;initial catalog=Northwind;persist security info=False;user id=sa;Password=sa;"

            CN.Open()

'NorthWind得到orders表的数据

            Dim adp As SqlDataAdapter = New SqlDataAdapter("select * from orders", CN)

            Dim ds As New DataSet()

            adp.Fill(ds)

            '得到数据视图

            dv = ds.Tables(0).DefaultView

        Catch ex As Exception

#If DEBUG Then

            Session("Error") = ex.ToString()

            Response.Redirect("../error.aspx")        '跳转程序的公共错误处理页面

#End If

        Finally

            '关闭连接

            CN.Close()

        End Try

        '排序

        dv.Sort = strSort

        Return dv

    End Function

 

    Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        If Not IsPostBack Then

            ViewState("strSort") = "orderid"

            dgOrder.DataSource = GetDv(ViewState("strSort").ToString())

            dgOrder.DataBind()

        End If

    End Sub

       '排序

    Private Sub dgOrder_SortCommand(ByVal source As Object, ByVal e As System.Web.UI.WebControls.DataGridSortCommandEventArgs) Handles dgOrder.SortCommand

        dgOrder.CurrentPageIndex = 0

          '得到排序的列

        ViewState("strSort") = e.SortExpression.ToString()

        dgOrder.DataSource = GetDv(ViewState("strSort").ToString())

        dgOrder.DataBind()

    End Sub

 

       '分页

    Private Sub dgOrder_PageIndexChanged(ByVal source As Object, ByVal e As System.Web.UI.WebControls.DataGridPageChangedEventArgs) Handles dgOrder.PageIndexChanged

          '得到分页的页号

        dgOrder.CurrentPageIndex = e.NewPageIndex

        dgOrder.DataSource = GetDv(ViewState("strSort").ToString())

        dgOrder.DataBind()

    End Sub

运行结果如下图所示:(点击列标头可以排序)

 

为了知道用户选择的是哪些记录,我们可以利用DataGridItemFindControl得到CheckBox的值,我们来添加一个按钮,再写如下代码:

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Dim item As DataGridItem

        Dim StrScript As String

        StrScript = "<script language=javascript>alert('"

          '循环表格的项,FindControl

        For Each item In Me.dgOrder.Items

            If CType(item.FindControl("cb"), System.Web.UI.WebControls.CheckBox).Checked Then

                Try

                    StrScript += item.Cells(1).Text & Space(2)

                Catch ex As Exception

                End Try

            End If

        Next

        StrScript += "被选择!')</script>"

        RegisterClientScriptBlock("系统消息", StrScript)

    End Sub

 

上面的代码RegisterClientScriptBlock添加Java Script脚本弹出对话框。(其实Vb Script的对话框比Java Script的对话框多更多的显示和控制方式,但Netscape的浏览器不支持,大家可根据相应的项目在程序里选择用哪种脚本)。

 

 

 

 

总结:

DataGrid是我们常用的Web 控件,有时我们还可以和DataList混合使用,通过修改HTML页,可以达到好的页面效果。上面只是一个例子,为了便于清楚整个过程,我把数据访问部分(SQL)写到了页面中。在软件开发中,我们一般把访问数据的部分写成数据层,页面调用数据层得到数据,这样逻辑清晰,修改和维护都很方便。

 

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‘Author:  李洪根

‘MAIL:   [email protected]

专栏:  http://www.csdn.net/develop/author/netauthor/lihonggen0/

如需引用,请指明出处! CSDN论坛VB版欢迎您!

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