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Asp.NET的DataGrid排序,选择和分页

2004-02-11 eNet&Ciweek

  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()

  '从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DataGridItem的FindControl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。</script>

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