Question

我使用Gridview来显示数据。在Gridview下，我为“问题”添加了一个标签，为“选项”添加了四个标签，为“正确答案”添加了一个标签，为问题答案的“解释”添加了一个标签。

正确的标签答案和解释在一个小组下。此面板应显示用户单击“显示答案”按钮并在再次单击该按钮时隐藏。在页面加载方法下，我写了“anspanel.Style.Add（”display“，”none“）;”隐藏面板但此行显示语法错误： - “当前上下文中不存在”name'anspanel'“。我无法弄清楚为什么。

以下是我的尝试： -

.aspx.cs =：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.SqlClient;
using System.Data;
using System.Configuration;


public partial class Student_Test : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        anspanel.Style.Add("display", "none");
        if (!IsPostBack)
        {
            GridView1.DataSource = GetData("SELECT top 2 Question, Option1, Option2, Option3, Option4, CorrectAns, Explanation FROM Questions");
            GridView1.DataBind();
        }
    }
}

private DataSet GetData(string query)
{
    string conString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
    SqlCommand cmd = new SqlCommand(query);
    using (SqlConnection con = new SqlConnection(conString))
    {
        using (SqlDataAdapter sda = new SqlDataAdapter())
        {
            cmd.Connection = con;
            sda.SelectCommand = cmd;
            using (DataSet ds = new DataSet())
            {
                sda.Fill(ds);
                return ds;
            }
        }
    }
}
}

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Test.aspx.cs" Inherits="Student_Test" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>

    <link rel="stylesheet" href="http://code.jquery.com/ui/1.8.3/themes/base/jquery-ui.css" />
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script type="text/javascript" src="http://code.jquery.com/ui/1.8.3/jquery-ui.js"></script>
<script type="text/javascript">
    var currentTab = 0;
    $(function () {
        $("#tabs").tabs({
            select: function (e, i) {
                currentTab = i.index;
            }
        });
    });
    $("#btnNext").live("click", function () {
        var tabs = $('#tabs').tabs();
        var c = $('#tabs').tabs("length");
        currentTab = currentTab == (c - 1) ? currentTab : (currentTab + 1);
        tabs.tabs('select', currentTab);
        $("#btnPrevious").show();
        if (currentTab == (c - 1)) {
            $("#btnNext").hide();
        } else {
            $("#btnNext").show();
        }
    });
    $("#btnPrevious").live("click", function () {
        var tabs = $('#tabs').tabs();
        var c = $('#tabs').tabs("length");
        currentTab = currentTab == 0 ? currentTab : (currentTab - 1);
        tabs.tabs('select', currentTab);
        if (currentTab == 0) {
            $("#btnNext").show();
            $("#btnPrevious").hide();
        }
        if (currentTab < (c - 1)) {
            $("#btnNext").show();
        }
    });

    $(function () {
        //$("#Panel2").hide();
        document.getElementById('form1').onsubmit = function () {
            return false;
        }//Avoid Reloading
        $("#Button1").click(function () {
            if ($('#anspanel').is(":hidden")) {
                $('#anspanel').show();
       
            }
            else {
                $('#anspanel').hide();
            }

            if ($("#Button1").val() == "Show Answer") {
                $("#Button1").val("Hide Answer");
            } else {
                $("#Button1").val("Show Answer");
            }
       

        });
      </script>
</head>
<body>
    <form id="form1" runat="server">
    <div>


        <div id="tabs">
    <ul>
        <li><a href="#tabs-1">Tab 1</a></li>
        <li><a href="#tabs-2">Tab 2</a></li>
        <li><a href="#tabs-3">Tab 3</a></li>
        <li><a href="#tabs-4">Tab 4</a></li>
        <li><a href="#tabs-5">Tab 5</a></li>
    </ul>
    <div id="tabs-1">
        <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false" OnRowDataBound="OnRowDataBound">
    <Columns>
        <asp:TemplateField>
            <ItemTemplate>

        <asp:Panel ID="Panel1" runat="server">

            <asp:Label ID="Label1" runat="server" Text='<%#Eval("Question") %>'></asp:Label>
            <br />
            <br />
            <br />
           <span>A-</span> <asp:Label ID="Label2" runat="server" Text='<%#Eval("Option1")%>'></asp:Label>
            <br />
            <br />
            <span>B-</span> <asp:Label ID="Label3" runat="server" Text='<%#Eval("Option2")%>'></asp:Label>
            <br />
            <br />
            <span>C-</span> <asp:Label ID="Label4" runat="server" Text='<%#Eval("Option3")%>'></asp:Label>
            <br />
            <br />
            <span>D-</span> <asp:Label ID="Label5" runat="server" Text='<%#Eval("Option4")%>'></asp:Label>
            <br />
            <br />
            &nbsp;&nbs<asp:Button ID="Button1" runat="server" Text="Show Answer"  />
            <br />

            <asp:Panel id="anspanel" runat="server">

                <span>Correct Answer is :-</span><asp:Label ID="Label6" runat="server" Text='<%#Eval("CorrectAns")%>'></asp:Label>
                <br />
                <br />
                <asp:Label ID="Label7" runat="server" Text='<%#Eval("Explanation")%>'></asp:Label>


            </asp:Panel>


        </asp:Panel>
        <br />
        <br />

                 </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

          </div>
    <div id="tabs-2">
        Tab 2 Content
    </div>
    <div id="tabs-3">
        Tab 3 Content
    </div>
     <div id="tabs-4">
        Tab 4 Content
    </div>
     <div id="tabs-5">
        Tab 5 Content
    </div>
</div>
<input type="button" id="btnPrevious" value="Previous" style = "display:none"/>
<input type="button" id="btnNext" value="Next" />

    
    </div>
    </form>
</body>
</html>

请告诉我错误的地方和解决方案。

错误： -

Server Error in '/' Application.

Object reference not set to an instance of an object.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error: 


Line 24:                     Panel panel1 = (Panel)GridView1.FindControl("Panel1");
Line 25:                     Panel anspanel = (Panel)GridView1.FindControl("anspanel");
Line 26:                     anspanel.Style.Add("display", "none");
Line 27:                 }
Line 28:             }

Source File: e:\Way2Success\Student\Test.aspx.cs    Line: 26 

Stack Trace: 


[NullReferenceException: Object reference not set to an instance of an object.]
   Student_Test.Page_Load(Object sender, EventArgs e) in e:\Way2Success\Student\Test.aspx.cs:26
   System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +51
   System.Web.UI.Control.OnLoad(EventArgs e) +95
   System.Web.UI.Control.LoadRecursive() +59
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2952

Answer 1

首先你需要绑定网格，否则就不会有任何行/控件。然后你必须找到你想要的控件并调整它的属性

Grid

如何使用C＃隐藏面板？

1 个答案: