radiobutton单击并避免页面刷新

Question

以下是我的代码，我正在做在线考试的项目。当我点击＆＃34; radiobutton＆＃34;时，整个页面会刷新。我该如何避免这种情况。

Imports System.Data.SqlClient

Partial Class Questions
Inherits System.Web.UI.Page

Dim cmd As New SqlCommand
Dim Result As Integer = 0
Dim Question_ID As Integer = Nothing
Dim strconn As String = ConfigurationManager.ConnectionStrings("DefaultConnection").ConnectionString
Dim con As New SqlConnection(strconn)


Protected Sub rblQuestion_SelectedIndexChanged(sender As Object, e As EventArgs) Handles rblQuestion1.SelectedIndexChanged
    CheckAnswer(rblQuestion1.SelectedValue, lblQuestion1.Text)

End Sub

Private Sub CheckAnswer(ByVal Answer As String, ByVal Question As String)
    Dim RetrievedAnswer As String = Nothing

    Try
        Dim daQuestionID As New SqlDataAdapter("select Question_ID from tblQuestions where Question='" & Question & "'", con)
        Dim dsQuestionID As New Data.DataSet
        Dim dtQuestionID As New Data.DataTable

        If Not con.State = Data.ConnectionState.Open Then con.Open()
        daQuestionID.Fill(dsQuestionID)
        dtQuestionID = dsQuestionID.Tables(0)

        If Not dtQuestionID.Rows.Count <= 0 Then
            If Not IsDBNull(dtQuestionID.Rows(0).Item("Question_ID")) Then
                Question_ID = dtQuestionID.Rows(0).Item("Question_ID")

            Else
                Exit Sub
            End If
        End If
    Catch ex As Exception

    End Try

    Try
        Dim daAnswer As New SqlDataAdapter("select Answer from tblQuestions where Question_ID=" & Question_ID, con)
        Dim dsAnswer As New Data.DataSet
        Dim dtAnswer As New Data.DataTable

        If Not con.State = Data.ConnectionState.Open Then con.Open()
        daAnswer.Fill(dsAnswer)
        dtAnswer = dsAnswer.Tables(0)

        If Not dtAnswer.Rows.Count <= 0 Then
            If Not IsDBNull(dtAnswer.Rows(0).Item("Answer")) Then
                RetrievedAnswer = dtAnswer.Rows(0).Item("Answer")
            End If
        End If

        If RetrievedAnswer = Answer Then
            Try
                Dim sr As New IO.StreamReader(System.AppDomain.CurrentDomain.BaseDirectory & "\\result.txt")
                Result = sr.ReadLine
                sr.Close()
                Result = Result + 1
                Dim sw As New IO.StreamWriter(System.AppDomain.CurrentDomain.BaseDirectory & "\\result.txt")
                sw.WriteLine(Result)
                sw.Close()
            Catch ex As Exception

            End Try

        End If
    Catch ex As Exception

    End Try
End Sub
Protected Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load

    If Not IsPostBack Then
        Try
            Dim daQuestions As New SqlDataAdapter("SELECT TOP 20 * FROM tblQuestions ORDER BY NEWID()", con)
            Dim dsQuestions As New Data.DataSet
            Dim dtQuestions As New Data.DataTable

            If Not con.State = Data.ConnectionState.Open Then con.Open()
            daQuestions.Fill(dsQuestions)
            dtQuestions = dsQuestions.Tables(0)

            If Not dtQuestions.Rows.Count <= 0 Then
                'For Question 1
                If Not IsDBNull(dtQuestions.Rows(0).Item("Question")) Then
                    lblQuestion1.Text = dtQuestions.Rows(0).Item("Question")
                End If
                If Not IsDBNull(dtQuestions.Rows(0).Item("Option1")) Then
                    rblQuestion1.Items(0).Text = dtQuestions.Rows(0).Item("Option1")
                End If
                If Not IsDBNull(dtQuestions.Rows(0).Item("Option2")) Then
                    rblQuestion1.Items(1).Text = dtQuestions.Rows(0).Item("Option2")
                End If
                If Not IsDBNull(dtQuestions.Rows(0).Item("Option3")) Then
                    rblQuestion1.Items(2).Text = dtQuestions.Rows(0).Item("Option3")
                End If
                If Not IsDBNull(dtQuestions.Rows(0).Item("Option4")) Then
                    rblQuestion1.Items(3).Text = dtQuestions.Rows(0).Item("Option4")
                End If
            End If
        Catch ex As Exception

        End Try




        'con.ConnectionString = ConfigurationManager.ConnectionStrings("DefaultConnection").ConnectionString
        cmd = New SqlCommand("insert into tblQuestions (Question, Option1, Option2, Option3, Option4,) values (@question, @option1, @option2, @option3, @option4)", con)
        cmd.Parameters.AddWithValue("@question", lblQuestion1.Text)
        cmd.Parameters.AddWithValue("@option1", rblQuestion1.Text)
        cmd.Parameters.AddWithValue("@option2", rblQuestion1.Text)
        cmd.Parameters.AddWithValue("@option3", rblQuestion1.Text)
        cmd.Parameters.AddWithValue("@option4", rblQuestion1.Text)
        'cmdInsertQuestion.Parameters.AddWithValue("@answer", txtAnswer.Text)
        Try
            con.Open()
            cmd.ExecuteNonQuery()
            con.Close()
            MsgBox(" ")
            'txtAnswer.Text = ""
            rblQuestion1.Text = ""
            rblQuestion1.Text = ""
            rblQuestion1.Text = ""
            rblQuestion1.Text = ""
        Catch ex As Exception
            'ex.Message
        End Try
    End If
End Sub



Protected Sub rblQuestion1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles rblQuestion1.SelectedIndexChanged

End Sub

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


    If IsPostBack Then
        Try
            Dim daQuestions As New SqlDataAdapter("SELECT TOP 20 * FROM tblQuestions ORDER BY NEWID()", con)
            Dim dsQuestions As New Data.DataSet
            Dim dtQuestions As New Data.DataTable
            rblQuestion1.ClearSelection()
            If Not con.State = Data.ConnectionState.Open Then con.Open()
            daQuestions.Fill(dsQuestions)
            dtQuestions = dsQuestions.Tables(0)

            If Not dtQuestions.Rows.Count <= 0 Then

                If Not IsDBNull(dtQuestions.Rows(0).Item("Question")) Then
                    lblQuestion1.Text = dtQuestions.Rows(0).Item("Question")
                End If
                If Not IsDBNull(dtQuestions.Rows(0).Item("Option1")) Then
                    rblQuestion1.Items(0).Text = dtQuestions.Rows(0).Item("Option1")
                End If
                If Not IsDBNull(dtQuestions.Rows(0).Item("Option2")) Then
                    rblQuestion1.Items(1).Text = dtQuestions.Rows(0).Item("Option2")
                End If
                If Not IsDBNull(dtQuestions.Rows(0).Item("Option3")) Then
                    rblQuestion1.Items(2).Text = dtQuestions.Rows(0).Item("Option3")
                End If
                If Not IsDBNull(dtQuestions.Rows(0).Item("Option4")) Then
                    rblQuestion1.Items(3).Text = dtQuestions.Rows(0).Item("Option4")
                End If
            End If



        Catch ex As Exception

        End Try


    End If
End Sub


Protected Sub btnSubmit_Click(sender As Object, e As EventArgs) Handles btnSubmit.Click
    Try
        Dim sr As New IO.StreamReader(System.AppDomain.CurrentDomain.BaseDirectory & "\\result.txt")
        Dim finalresult As Integer = sr.ReadLine
        sr.Close()
        Response.Write("<script type='text/javascript'>alert('Your Score is : " & finalresult & "');</script>")
        Dim sw As New IO.StreamWriter(System.AppDomain.CurrentDomain.BaseDirectory & "\\result.txt")
        sw.WriteLine(0)
        sw.Close()
    Catch ex As Exception

    End Try
End Sub
End Class

Answer 1

click事件执行服务器回发，这会导致页面刷新。 Ajax是可行的方法，请查看https://ajaxcontroltoolkit.codeplex.com/或api.jquery.com/jquery.ajax/以开始使用。