我是AS400程序员，要求使用vb.net在asp.net中编写程序。我以前从未这样做过，而且我遇到了在Gridview中填充列表框的问题。我已经研究了这个主题好几天，但是我在实例中找到的所有代码都没有用。请原谅任何非常糟糕的代码，因为我对.net这么新，我相信这可以写得更好。我感谢您提供的任何帮助。网格是“AdjusterList”，列表框叫“MAICD”。我认为'失败/糟糕'的代码 Public Sub AdjusterList_RowDataBound。它在数据绑定之前给出了一个null异常错误; oCtrl.DataSource = oRs
我正在使用由高级.net程序员提供给我的代码，他无法为这个新手提供更多帮助。只是Fyi ....
这是我的aspx。
<div id="div1" runat="server">
<asp:GridView ID="AdjusterList" runat="server" Width="1100px"
ClientIDMode="Static" AllowSorting="True"
AutoGenerateColumns="False"
OnRowCommand="AdjusterList_RowCommand"
OnRowEditing="AdjusterList_RowEditing"
OnRowUpdating="AdjusterList_RowUpdating"
OnRowDeleting="AdjusterList_RowDeleting"
OnRowCancelingEdit="AdjusterList_RowCancelingEdit"
OnRowDataBound="AdjusterList_RowDataBound"
DataKeyNames="INSCD, INSSEQ"
ShowHeaderWhenEmpty="True" EditRowStyle-BackColor="#FF9900" PageSize="20"
EmptyDataText="NO RECORDS FOUND FOR THIS INSURER"
ShowFooter="True"EnableViewState="true">
<EditRowStyle BackColor="#FF9900" />
<RowStyle BackColor="White" ForeColor="Black" />
<Columns>
<asp:TemplateField>
<ItemTemplate>
<asp:LinkButton id="btnedit" runat="server" CommandName="Edit"/>
</ItemTemplate>
<EditItemTemplate>
<asp:LinkButton id="btnupdate" runat="server" CommandName="Update" Text="Save" />
<asp:LinkButton id="btncancel" runat="server" CommandName="Cancel" Text=Cancel"/>
</EditItemTemplate>
<FooterTemplate>
<asp:LinkButton id="btninsert" runat="server" CommandName="Insert" Text="Insert"/>
</FooterTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText ="Mail Code" ItemStyle-HorizontalAlign="Center">
<ItemTemplate>
<asp:Label ID="lblmaicd" runat="server" Text='<%# Bind("MAICD")%>'></asp:Label>
</ItemTemplate>
<EditItemTemplate>
<asp:ListBox ID="MAICD" runat="server" Rows="1"DataTextField="Text"
DataValueField='<%# Bind("MAICD")%></asp:ListBox>
</EditItemTemplate>
<FooterTemplate>
<asp:ListBox ID="MAICD" runat="server" width="200" DataTextField="Text">
</asp:ListBox>
</FooterTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
我的代码背后......
Imports System.Data
Imports System.Data.SqlClient
Imports System.Data.OleDb
Public Class EditAdjusterData
Inherits System.Web.UI.Page
Protected Sub Page_Load(ByVal sender As Object, ByVal e AsSystem.EventArgs)
Dim sAdjuster As String = Session("Adjuster")
Dim sSeqNo As String = Session("SeqNo")
PopulateEdit(sAdjuster, sSeqNo, dateok)
If IsPostBack Then
'divEdit.Visible = False
'divSelect.Visible = True
'ShowForm()
Else
AdjusterList.DataBind()
'divEdit.Visible = True
'divSelect.Visible = False
End If
End Sub
Protected Sub PopulateEdit(sValue As String, sValue2 As String, sValue3 As String)
' CALL TO PGRTSTLIB FILE INSP TO GET INSURER NAME
' 2ND CALL TO PGRTSTLIB FILE INSD
Dim oConn As New OleDbConnection()
Dim sConn As String = ""
Dim oCmd As New OleDbCommand()
Dim oAdapter As New OleDbDataAdapter()
Dim oRs As DataSet = New DataSet
Dim sSql As String = ""
sConn = "Provider=IBMDA400.DataSource.1;
oConn = New OleDb.OleDbConnection(sConn)
oConn.Open()
sSql = "SELECT INSCD, INSSEQ, MAICD, MAISEQ, (substr(char(EFFDT),5,2) || '-' || substr(char(EFFDT),7,2) || '-' || substr(char(EFFDT),1,4)) AS EFFDT, (substr(char(CANDT),5,2) || '-' || substr(char(CANDT),7,2) || '-' || substr(char(CANDT),1,4)) AS CANDT, ACCFIL FROM PGRTSTLIB.INSD WHERE INSCD = '" & sValue & "' "
oCmd = New OleDbCommand(sSql, oConn)
Session(INSCD) = INSCD
Session(EFFDT) = EFFDT
Session(MAICD) = MAICD
Session("CANDT") = CANDT
oCmd.CommandType = CommandType.Text
oAdapter.SelectCommand = oCmd
oAdapter.Fill(oRs, "Data")
Dim sMailCode As String = " "
Dim sMailSeq As String = " "
Dim pRow As DataRow
For Each pRow In oRs.Tables("Data").Rows
sMailCode = pRow("MAICD").ToString()
Next
Session(sMailCode) = MAICD
Session(MAICD) = sMailCode
Session(sMailCode) = sMailCode
AdjusterList.DataSource = oRs
'AdjusterList.DataBind()
'If sMailCode <> " " Then
' PopulateMailCode(sMailCode)
'End If
oRs.Dispose()
oAdapter.Dispose()
oCmd.Dispose()
oConn.Dispose()
End Sub
Protected Sub AdjusterList_PageIndexChanging(ByVal sender As Object,
ByVal e As System.Web.UI.WebControls.GridViewPageEventArgs)
AdjusterList.PageIndex = e.NewPageIndex
AdjusterList.DataBind()
End Sub
Protected Sub AdjusterList_RowCommand(ByVal sender As Object,
ByVal e As System.Web.UI.WebControls.GridViewCommandEventArgs)
End Sub
Protected Sub AdjusterList_RowCreated(ByVal sender As Object,
ByVal e As System.Web.UI.WebControls.GridViewRowEventArgs)
End Sub
Public Sub AdjusterList_RowDataBound(ByVal Sender As Object,
ByVal e As GridViewRowEventArgs) Handles AdjusterList.RowDataBound
If e.Row.RowType = DataControlRowType.DataRow Then
If e.Row.FindControl("MAICD") IsNot Nothing Then
Dim MAICD As ListBox = e.Row.FindControl("MAICD")
'If (e.Row.RowState And DataControlRowState.Edit) > 0 Then
BindAjusterList()
End If
End If
End Sub
Public Sub BindAjusterList()
Dim oConn As New OleDbConnection()
Dim sConn As String = ""
Dim oCmd As New OleDbCommand()
Dim oAdapter As New OleDbDataAdapter()
Dim oRs As DataSet = New DataSet
Dim sSql As String = ""
sConn = "Provider=IBMDA400.DataSource.1; "
oConn = New OleDb.OleDbConnection(sConn)
oConn.Open()
'sSql = "SELECT MAICD as Value, MAICD AS Text from PGRTSTLIB.INSM order by MAICD"
sSql = "SELECT MAICD As Value, MAICD AS TEXT from PGRTSTLIB.INSM"
oCmd = New OleDbCommand(sSql, oConn)
'oCmd.Parameters.Add(New SqlParameter("@Type", Insurer))
oCmd.CommandType = CommandType.Text
oAdapter.SelectCommand = oCmd
oAdapter.Fill(oRs, "ListBox")
Dim oCtrl As ListBox
oCtrl = AdjusterList.FindControl("MAICD")
oCtrl.Items.Add(New ListItem("", ""))
oCtrl.DataSource = oRs
oCtrl.DataBind()
oCtrl.Items.Insert(0, New ListItem(String.Empty, String.Empty))
If Len(sValue) > 0 Then
oCtrl.SelectedValue = sValue
Else
sValue = " "
End If
oRs.Dispose()
oAdapter.Dispose()
oCmd.Dispose()
oConn.Dispose()
End Sub
Public Sub AdjusterList_RowEditing(ByVal sender As Object,
ByVal e As System.Web.UI.WebControls.GridViewEditEventArgs)
AdjusterList.EditIndex = e.NewEditIndex
AdjusterList.DataBind()
End Sub
Protected Sub AdjusterList_RowUpdating(ByVal sender As Object,
ByVal e As System.Web.UI.WebControls.GridViewUpdateEventArgs)
' Dim row As GridViewRow = DirectCast(SubsidaryList.Rows(e.RowIndex), GridViewRow)
Dim INSCD As String = DirectCast(AdjusterList.Rows(e.RowIndex).Cells (0).FindControl ("INSCD"), TextBox).Text
Dim INSSEQ As String = DirectCast(AdjusterList.Rows(e.RowIndex).Cells(1).FindControl("INSSEQ"), TextBox).Text
Dim MAICD As String = DirectCast(AdjusterList.Rows(e.RowIndex).Cells(2).FindControl("MAICD"), ListBox).Text
Dim MAISEQ As String = DirectCast(AdjusterList.Rows(e.RowIndex).Cells(3).FindControl("MAISEQ"), TextBox).Text
Dim EFFDT As String = DirectCast(AdjusterList.Rows(e.RowIndex).Cells(4).FindControl("EFFDT"), TextBox).Text
Dim CANDT As String = DirectCast(AdjusterList.Rows(e.RowIndex).Cells(5).FindControl("CANDT"), TextBox).Text
Dim ACCFIL As String = DirectCast(AdjusterList.Rows(e.RowIndex).Cells(6).FindControl("ACCFIL"), TextBox).Text
AdjusterList.EditIndex = -1
AdjusterList.DataBind()
' New Data to DataBind to sql datasource and resend page after RECORD updated
Response.Redirect("EditAdjusterData.aspx")
End Sub
Protected Sub AdjusterList_RowCancelingEdit() Handles AdjusterList.RowCancelingEdit
AdjusterList.EditIndex = -1
AdjusterList.DataBind()
End Sub
End Class
我对.net很新，我可能不完全理解每一个例子。我认为高级.net程序员认为这很有趣:(
非常感谢，如果您有任何帮助，请随时与我联系。我只需要填充这个填充列表框。我删除了我认为与此列表框问题无关的任何代码。
答案 0 :(得分：0)
在您的标记中，您应该将ListBox的DataValueField属性更改为“Value”字符串，因为它是您在查询("SELECT MAICD As Value, MAICD AS TEXT from PGRTSTLIB.INSM")中为该属性提供的别名：
<asp:ListBox ID="MAICD" runat="server" Rows="1"DataTextField="Text" DataValueField="Value"></asp:ListBox>
此外，在RowDataBound事件中，您正在使用FindControl方法检索该行的ListBox实例，但之后您将在BindAjusterList()方法中再次检索它。尝试更改方法以接收找到的控件：
Public Sub AdjusterList_RowDataBound(ByVal Sender As Object, ByVal e As GridViewRowEventArgs) Handles AdjusterList.RowDataBound
If e.Row.RowType = DataControlRowType.DataRow Then
If e.Row.FindControl("MAICD") IsNot Nothing Then
Dim MAICD As ListBox = e.Row.FindControl("MAICD")
BindAjusterList(MAICD)
End If
End If
End Sub
Public Sub BindAjusterList(ByVal oCtrl As ListBox)
' existing logic
oCtrl.Items.Add(New ListItem("", ""))
oCtrl.DataSource = oRs
oCtrl.DataBind()
' existing logic
End Sub