关于winfrom里DataGrid的自动分页的问题！

[blue_apple]

各位老大！我又来提问题了！

我VS里使用DataGrid的属性生成器给DataGrid设定了自动分页的功能，但是执行的时候，我按DataGrid下面的分页按钮，DataGrid没有任何反应，依然是显示首页，请问这问题如何解决？谢谢！

[goody9807]

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

[blue_apple]

TO： goody9807()

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

这句不是很明白，我是用VB写的，能解释一下这句话吗？

[blue_apple]

奇怪，我把搜索按钮程序加进去：
Private Sub DataGrid1_PageIndexChanged(ByVal source As Object, ByVal e As System.Web.UI.WebControls.DataGridPageChangedEventArgs) Handles DataGrid1.PageIndexChanged

DataGrid1.CurrentPageIndex = e.NewPageIndex
Dim txtSql As String
Dim a As String = DropDownList1.SelectedValue

If DropDownList1.SelectedValue = "用户编号" Then txtSql = "select * from tbyh where 用户编号=" & TextBox1.Text.Trim
If DropDownList1.SelectedValue = "用户名称" Then txtSql = "select * from tbyh where 用户名称 like '%" & TextBox1.Text & "%'"
If DropDownList1.SelectedValue = "用户地址" Then txtSql = "select * from tbyh where 用户地址 like '%" & TextBox1.Text & "%'"
If DropDownList1.SelectedValue = "用户电话" Then txtSql = "select * from tbyh where 用户电话 like '%" & TextBox1.Text & "%'"


Dim SqlDa2 As New SqlClient.SqlDataAdapter(txtSql, Sqlcnn)
SqlDa2.Fill(dt2, "tbyh")
Table2 = dt2.Tables(0)
DataGrid1.DataSource = Table2
DataGrid1.DataBind()

End Sub
竟然成功了，但是我把程序改为：
Private Sub DataGrid1_PageIndexChanged(ByVal source As Object, ByVal e As System.Web.UI.WebControls.DataGridPageChangedEventArgs) Handles DataGrid1.PageIndexChanged

DataGrid1.CurrentPageIndex = e.NewPageIndex

DataGrid1.DataSource = Table2
DataGrid1.DataBind()

End Sub
就不成功，请问是什么原因？如何解决？

[zhrenxi]

事件发生后，你的Table2变量已经丢失参数了吧，所以你分页的时候，这个Table2已经是null，以至出现------------无效的 CurrentPageIndex 值。它必须大于等于 0 且小于 PageCount。
这样的错误，所以问题要解决，你就必须绑定DataGrid以前，再运行一次绑定数据院的函数。

[zhrenxi]

还有，你这个Private Sub DataGrid1_PageIndexChanged(ByVal source As Object, ByVal e As System.Web.UI.WebControls.DataGridPageChangedEventArgs) Handles DataGrid1.PageIndexChanged
必须从事件中添加的。否则是不会运行的。

[blue_apple]

Private Sub DataGrid1_PageIndexChanged(ByVal source As Object, ByVal e As System.Web.UI.WebControls.DataGridPageChangedEventArgs) Handles DataGrid1.PageIndexChanged
必须从事件中添加的。什么意思啊？

必须绑定DataGrid以前，再运行一次绑定数据院的函数。

这样就是在运行一次按钮搜索的程序？可不可以不运行啊？我如何可以把上次运行的Table2保存下来？

[zhrenxi]

那你说你的Private Sub DataGrid1_PageIndexChanged(ByVal source As Object, ByVal e As System.Web.UI.WebControls.DataGridPageChangedEventArgs) Handles DataGrid1.PageIndexChanged
是怎么出来的？

[blue_apple]

在VS开发界面里头选的咯，先在左边选DataGrid1，然后在右边选PageIndexChanged

[zhrenxi]

是的，你双击那事件就出现了Private Sub DataGrid1_PageIndexChanged(ByVal source As Object, ByVal e As System.Web.UI.WebControls.DataGridPageChangedEventArgs) Handles DataGrid1.PageIndexChanged
是吧？那这没问题啊

[blue_apple]

问题是：
必须绑定DataGrid以前，再运行一次绑定数据院的函数。

这样就是在运行一次按钮搜索的程序？可不可以不运行啊？我如何可以把上次运行的Table2保存下来？

我已经把Table2定义为全局变量了，怎么数据还保存不了？要如何才能不需要在运行一次搜索程序啊？

[zhrenxi]

Private Sub DataGrid1_PageIndexChanged(ByVal source As Object, ByVal e As System.Web.UI.WebControls.DataGridPageChangedEventArgs) Handles DataGrid1.PageIndexChanged

DataGrid1.CurrentPageIndex = e.NewPageIndex

//还是中间这里要加代码

DataGrid1.DataBind()

End Sub

你再什么地方对Datgrid1加数据的，是什么代码，你再到这里面写一次就可以了

[zhrenxi]

全局变量也不行的

[zhrenxi]

响应事件之后， 页面重新打开，程序再依次执行，首先又要定义参数，所以你定义的全局变量又会重新调用一次，根本不可能保存你上次的table2的

[amendajing]

up

[zhrenxi]

你把Table2绑定数据的部分复制粘贴在 ---//还是中间这里要加代码-------------这里应该就可以了，试一下

[blue_apple]

Public Class sfcx
Inherits System.Web.UI.Page
Dim Sqlcnn As SqlConnection
Dim SqlDa As New SqlClient.SqlDataAdapter
Dim dt2 As New DataSet
Dim Table2 As New DataTable

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'在此处放置初始化页的用户代码
Sqlcnn = New SqlClient.SqlConnection
Sqlcnn.ConnectionString = "workstation id=WIN2003;packet size=4096;user id=sa;Pwd=123456789;data source=""192.168.0.2"";pers" & _
"ist security info=False;initial catalog=sfxtdb"
Sqlcnn.Open()
End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
DataGrid1.Visible = True
Panel1.Visible = True
DataGrid2.Visible = False

Dim txtSql As String
Dim a As String = DropDownList1.SelectedValue

If DropDownList1.SelectedValue = "用户编号" Then txtSql = "select * from tbyh where 用户编号=" & TextBox1.Text.Trim
If DropDownList1.SelectedValue = "用户名称" Then txtSql = "select * from tbyh where 用户名称 like '%" & TextBox1.Text & "%'"
If DropDownList1.SelectedValue = "用户地址" Then txtSql = "select * from tbyh where 用户地址 like '%" & TextBox1.Text & "%'"
If DropDownList1.SelectedValue = "用户电话" Then txtSql = "select * from tbyh where 用户电话 like '%" & TextBox1.Text & "%'"


Dim SqlDa2 As New SqlClient.SqlDataAdapter(txtSql, Sqlcnn)
SqlDa = SqlDa2
SqlDa2.Fill(dt2, "tbyh")
SqlDa.Fill(dt2, "tbyh")
Table2 = dt2.Tables(0)
DataGrid1.DataSource = Table2
DataGrid1.DataBind()
这就是我的按钮程序。

我把它加入进去是可以的，你可以看看上面我贴出来的一个成功的程序。但这不是我的目的。

[zhrenxi]

那你的目的是什么？

[blue_apple]

我不希望PageIndexChanged中有：
If DropDownList1.SelectedValue = "用户编号" Then txtSql = "select * from tbyh where 用户编号=" & TextBox1.Text.Trim
If DropDownList1.SelectedValue = "用户名称" Then txtSql = "select * from tbyh where 用户名称 like '%" & TextBox1.Text & "%'"
If DropDownList1.SelectedValue = "用户地址" Then txtSql = "select * from tbyh where 用户地址 like '%" & TextBox1.Text & "%'"
If DropDownList1.SelectedValue = "用户电话" Then txtSql = "select * from tbyh where 用户电话 like '%" & TextBox1.Text & "%'"

这段程序，因为万一在这一过程中DropDownList1或TextBox1的值被人为改变，那整个DataGrid就变了，不是原来那个了。

[zhrenxi]

那你的意思就是要保存Table2？

[blue_apple]

差不多吧，反正使得，人为的改动DropDownList1或TextBox1的值也不会改变原来的DataGrid里面的值就OK了！系统操作员的水平不高，就怕她们不听话乱搞的话又说我的系统有问题就麻烦了。

下班了，下午在继续讨论吧！谢谢高手！