コントロールを Web フォームに動的に挿入するプログラムを作成しています。変数に応じて、テキスト ボックス、ラジオ ボタンのセット、またはチェックボックスのセットのいずれかを追加します。後で、ユーザーが送信ボタンをクリックした後、ユーザーが正しい回答を送信しているかどうかを判断するためにコントロールを使用する必要がありますが、コントロールの ID を参照しようとすると、「txtAnser が宣言されていません。アクセスできない可能性があります」というメッセージが表示されます。保護レベルのためです。
.aspx ページは次のとおりです (マスター ページの標準コンテンツ ページです)。
<%@ Page Title="" Language="VB" MasterPageFile="~/top.master" AutoEventWireup="false"
CodeFile="test_page.aspx.vb" Inherits="Default2" %>
<asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="PageContent" Runat="Server">
<asp:SqlDataSource ID="sdsQuestionPuller" runat="server"
ConnectionString="<%$ ConnectionStrings:SchoolhouseConnectionString6 %>"
SelectCommand="SELECT QuestionText, AnswerType, PossibleAnswers, CorrectAnswers
FROM Questions WHERE (SubjectID = @SubjectID) AND (QuestionOrder = @QuestionOrder)">
<SelectParameters>
<asp:SessionParameter Name="SubjectID" SessionField="SubjectID" />
<asp:SessionParameter Name="QuestionOrder" SessionField="PageNumber" />
</SelectParameters>
</asp:SqlDataSource>
<asp:SqlDataSource ID="sdsMaxQuestions" runat="server"
ConnectionString="<%$ ConnectionStrings:SchoolhouseConnectionString7 %>"
SelectCommand="SELECT MAX(QuestionOrder) AS LastQuestion FROM Questions GROUP BY SubjectID HAVING (SubjectID = @SubjectID)">
<SelectParameters>
<asp:SessionParameter Name="SubjectID" SessionField="SubjectID" />
</SelectParameters>
</asp:SqlDataSource>
<div>
<asp:Label ID="lblInstructionHolder" runat="server"></asp:Label>
</div>
<div>
<asp:Label ID="lblQuestionHolder" runat="server"></asp:Label>
</div>
<asp:PlaceHolder ID="plhQuestionHolder" runat="server"></asp:PlaceHolder>
<div>
<asp:Button ID="btnSubmit" Text="Submit" runat="server" />
</div>
</asp:Content>
ここにコード ビハインドがあります。select case ステートメントで txtAnswer コントロールを参照しようとすると、送信ボタンのクリック イベントで問題が発生します。
Imports System.Data
Partial Class Default2
Inherits System.Web.UI.Page
Dim intMaxPage As Integer
'QuestionText, AnswerType, PossibleAnswers, CorrectAnswers
Dim strQuestion As String
Dim strQuestionType As String
Dim astrPossibleAnswers() As String
Dim intNumberOfPossAnswers As Integer
Dim astrCorrectAnswers() As String
Dim intNumberOfCorrectAnswers As Integer
Protected Sub Page_Init(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Init
End Sub
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
'Load up the variables(make sure data is retrieved, create a view from the source, retrieve the only row, assing the item(s) from the row to variables)
sdsMaxQuestions.DataBind()
Dim dtvLastPageView As DataView = CType(sdsMaxQuestions.Select(DataSourceSelectArguments.Empty), DataView)
Dim dtrLastPageRow As DataRowView = dtvLastPageView.Item(0)
intMaxPage = CInt(Trim(dtrLastPageRow.Item(0).ToString))
Dim dtvQuestionsView As DataView = CType(sdsQuestionPuller.Select(DataSourceSelectArguments.Empty), DataView)
Dim dtrQuestionsRow As DataRowView = dtvQuestionsView.Item(0)
strQuestion = Trim(dtrQuestionsRow.Item(0).ToString)
strQuestionType = Trim(dtrQuestionsRow.Item(1).ToString)
astrPossibleAnswers = Split(Trim(dtrQuestionsRow.Item(2).ToString), ";")
intNumberOfPossAnswers = astrPossibleAnswers.Count
astrCorrectAnswers = Split(Trim(dtrQuestionsRow.Item(3).ToString), ";")
intNumberOfCorrectAnswers = astrCorrectAnswers.Count
'Finish loading controls
lblQuestionHolder.Text = strQuestion
Select Case strQuestionType
Case "checkbox"
lblInstructionHolder.Text = "Choose the correct answer(s)."
Case "radio"
lblInstructionHolder.Text = "Choose the best answer."
Case "fillintheblank"
lblInstructionHolder.Text = "Please fill in the blank, case doesn't count, spelling does."
Case Else
lblInstructionHolder.Text = "Somethings wrong, contact admin"
End Select
'Generate the controls for answers...
GenerateControls()
End Sub
Protected Sub btnSubmit_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnSubmit.Click
'Declare the variables, get any existing values, then check to see if the answer is correct, display a message and go to the next page or store the score.
Dim intNumberRight As Integer = 0
Dim intNumberTotal As Integer = 0
If Not (Session("NumberRight") = Nothing) Then
intNumberRight = CInt(Session("NumberRight"))
End If
If Not (Session("NumberTotal") = Nothing) Then
intNumberTotal = CInt(Session("NumberTotal"))
End If
Select Case strQuestionType
Case "checkbox"
Case "radio"
Case "fillintheblank"
'Here is where I am having issues
If txtAnswer Is Not Nothing Then
End If
If txtAnswer.text.ToLower = astrCorrectAnswers(0).ToLower Then
End If
Case Else
MsgBox("Somethings wrong, contact admin")
End Select
If intMaxPage = CType(Session("PageNumber"), Integer) Then
Response.Redirect("user_landing.aspx")
Else
Session("PageNumber") = CType(Session("PageNumber"), Integer) + 1
Response.Redirect("test_page.aspx")
End If
End Sub
Private Sub GenerateControls()
'Make the correct controls depending on the type
Dim conDivHolder As HtmlGenericControl = New HtmlGenericControl("div")
Select Case strQuestionType
Case "checkbox"
For i As Integer = 0 To intNumberOfPossAnswers - 1
Dim chkAnswer As CheckBox = New CheckBox
With chkAnswer
.ID = "chkAnswer" + i.ToString
.Text = astrPossibleAnswers(i)
End With
conDivHolder.Controls.Add(chkAnswer)
Next
Case "radio"
For i As Integer = 0 To intNumberOfPossAnswers - 1
Dim rdoAnswer As RadioButton = New RadioButton
With rdoAnswer
.ID = "rdoAnswer" + i.ToString
.Text = astrPossibleAnswers(i)
.GroupName = "rdoGroup"
End With
conDivHolder.Controls.Add(rdoAnswer)
Next
Case "fillintheblank"
Dim txtAnswer As TextBox = New TextBox
txtAnswer.ID = "txtAnswer"
conDivHolder.Controls.Add(txtAnswer)
Case Else
Dim lblOops As Label = New Label
lblOops.Text = "Oops, contact admin"
conDivHolder.Controls.Add(lblOops)
End Select
plhQuestionHolder.Controls.Add(conDivHolder)
End Sub
End Class
誰かが私がしなければならないことを指摘できれば、私はそれを感謝します.
ありがとう、サイモン