我在singleKingButton.Checked = true上得到一个空引用异常;在页面加载事件中。如果我发表评论，那么我仍然可以在下一行设置日期。奇怪的是页面加载很好，当我点击提交按钮，我得到错误。提前谢谢！
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace garrettPenfieldUnit4
{
public partial class Default : System.Web.UI.Page
{
Reservation newReservation = new Reservation();
//Load events, automatically inserts todays date and selects the single king radio button
protected void Page_Load(object sender, EventArgs e)
{
UnobtrusiveValidationMode = System.Web.UI.UnobtrusiveValidationMode.None;
singleKingButton.Checked = true;
arrivalDateBox.Text = DateTime.Today.ToShortDateString();
}
//When submit button is clicked show the two confirmation labels.
protected void submitButton_Click(object sender, EventArgs e)
{
newReservation.ArrivalDate = Convert.ToDateTime(arrivalDateBox.Text);
newReservation.DepartureDate = Convert.ToDateTime(departureDateBox.Text);
newReservation.NoOfPeople = peopleDropDown.SelectedIndex;
newReservation.SpecialRequests = specialRequestsBox.Text;
newReservation.FirstName = firstNameBox.Text;
newReservation.LastName = lastNameBox.Text;
newReservation.Email = addressBox.Text;
newReservation.Phone = telephoneNumberBox.Text;
newReservation.PreferredMethod = contactDropDown.SelectedIndex.ToString();
if (singleKingButton.Checked)
{
newReservation.BedType = "Single King";
}
if (twoQueensButton.Checked)
{
newReservation.BedType = "Two Queens";
}
if (singleQueenButton.Checked)
{
newReservation.BedType = "Single Queen";
}
Session["Reservation"] = newReservation;
Response.Redirect("~/ConfirmationPage.aspx");
}
//When the clear button is clicked clear the form and reset fields to their default values
protected void clearButton_Click(object sender, EventArgs e)
{
arrivalDateBox.Text = DateTime.Today.ToShortDateString();
departureDateBox.Text = String.Empty;
peopleDropDown.SelectedIndex = 0;
singleKingButton.Checked = true;
twoQueensButton.Checked = false;
singleQueenButton.Checked = false;
specialRequestsBox.Text = String.Empty;
firstNameBox.Text = String.Empty;
lastNameBox.Text = String.Empty;
addressBox.Text = String.Empty;
telephoneNumberBox.Text = String.Empty;
contactDropDown.SelectedIndex = 0;
}
}
}
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="garrettPenfieldUnit4.Default" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Royal Inn and Suites</title>
<link href="Content/bootstrap.css" rel="stylesheet" />
<link href="Content/Main.css" rel="stylesheet" />
<script src="Scripts/jquery-1.9.1.min.js"></script>
<script src="Scripts/bootstrap.min.js"></script>
</head>
<body>
<form id="form1" runat="server" defaultbutton="submitButton" defaultfocus="arrivalDateBox">
<div class="container">
<div id="page-header">
<h1 style="color: blue;">Royal Inn and Suites</h1>
<p style="color: red; font-style: italic;">
Where you're always treated like royalty
</div>
<h3 style="color: blue;">Reservation Request</h3>
<asp:ValidationSummary ID="ValidationSummary1" runat="server" ForeColor="Red" />
</div>
<div id="form-group">
<h4>Request Data</h4>
<div>
Arrival Date<asp:RequiredFieldValidator ID="arrivalDateBoxValidator" runat="server" ErrorMessage="Arrival date is required"
ControlToValidate="arrivalDateBox" ForeColor="Red" Display="Dynamic">*</asp:RequiredFieldValidator>
<asp:CompareValidator ID="arrivalDateValidator" runat="server" ErrorMessage="Arrival date must be before departure date."
ControlToValidate="arrivalDateBox" ControlToCompare="departureDateBox" Display="Dynamic"
Operator="DataTypeCheck" Type="Date" ForeColor="red">*</asp:CompareValidator>
</div>
<div>
<asp:TextBox ID="arrivalDateBox" runat="server" CssClass="form-control"></asp:TextBox>
</div>
<div>Departure Date</div>
<div>
<asp:TextBox ID="departureDateBox" runat="server" CssClass="form-control"></asp:TextBox>
<asp:RequiredFieldValidator ID="departureDateBoxValidator" runat="server" ErrorMessage="Departure date is required"
ControlToValidate="departureDateBox" ForeColor="Red" Display="Dynamic">*</asp:RequiredFieldValidator>
<asp:CompareValidator ID="departureDateCompareValidator" runat="server" ErrorMessage="Departure date must be after arrival date"
ControlToValidate="departureDateBox" ForeColor="Red" ControlToCompare="arrivalDateBox" Display="Dynamic" Operator="GreaterThan"
Type="Date">*</asp:CompareValidator>
</div>
<div>Number of People</div>
<div>
<asp:DropDownList ID="peopleDropDown" runat="server" CssClass="form-control">
<asp:ListItem>1</asp:ListItem>
<asp:ListItem>2</asp:ListItem>
<asp:ListItem>3</asp:ListItem>
<asp:ListItem>4</asp:ListItem>
</asp:DropDownList>
</div>
<div>
<div>
Bed Type
<asp:RadioButton ID="singleKingButton" runat="server" Text="King" GroupName="bedType" />
<asp:RadioButton ID="twoQueensButton" runat="server" Text="Two Queens" GroupName="bedType" />
<asp:RadioButton ID="singleQueenButton" runat="server" Text="Single Queen" GroupName="bedType" />
</div>
</div>
<h3>Special Requests</h3>
<div>
<asp:TextBox ID="specialRequestsBox" runat="server" TextMode="MultiLine" CssClass="form-control"></asp:TextBox>
</div>
<h3>Contact Information</h3>
<div>First Name</div>
<asp:TextBox ID="firstNameBox" runat="server" CssClass="form-control"></asp:TextBox>
<asp:RequiredFieldValidator ID="firstNameBoxValidator" runat="server" ErrorMessage="First name is required"
ControlToValidate="firstNameBox" ForeColor="Red">*</asp:RequiredFieldValidator>
<div>Last Name</div>
<asp:TextBox ID="lastNameBox" runat="server" CssClass="form-control"></asp:TextBox>
<asp:RequiredFieldValidator ID="lastNameBoxValidator" runat="server" ErrorMessage="Last name is required"
ControlToValidate="lastNameBox" ForeColor="Red">*</asp:RequiredFieldValidator>
<div>E-mail Address</div>
<asp:TextBox ID="addressBox" runat="server" CssClass="form-control"></asp:TextBox>
<asp:RequiredFieldValidator ID="addressBoxValidator" runat="server" ErrorMessage="Email address is required"
ControlToValidate="addressBox" ForeColor="Red" Display="Dynamic">*</asp:RequiredFieldValidator>
<asp:RegularExpressionValidator ID="addressBoxExpressionValidator1" runat="server" ErrorMessage="Invalid Email"
ControlToValidate="addressBox" ForeColor="Red" Display="Dynamic" ValidationExpression="\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*">*</asp:RegularExpressionValidator>
<div>Telephone Number</div>
<asp:TextBox ID="telephoneNumberBox" runat="server" CssClass="form-control"></asp:TextBox>
<asp:RequiredFieldValidator ID="telephoneNumberBoxValidator" runat="server" ErrorMessage="Telephone Number is required"
ControlToValidate="telephoneNumberBox" ForeColor="Red" Display="Dynamic">*</asp:RequiredFieldValidator>
<asp:RegularExpressionValidator ID="telephoneExpressionValidator" runat="server"
ErrorMessage="Invalid phone number" ControlToValidate="telephoneNumberBox" ForeColor="red" Display="Dynamic" ValidationExpression="((\(\d{3}\) ?)|(\d{3}-))?\d{3}-\d{4}">*</asp:RegularExpressionValidator>
<div>Preferred Method of Contact</div>
<asp:DropDownList ID="contactDropDown" runat="server" CssClass="form-control">
<asp:ListItem>E-mail</asp:ListItem>
<asp:ListItem>Telephone</asp:ListItem>
</asp:DropDownList>
<div>
<asp:Button ID="submitButton" class="btn btn-primary btn-space" runat="server" Text="Submit" OnClick="submitButton_Click" />
<asp:Button ID="clearButton" class="btn btn-primary btn-space" runat="server" Text="Clear" OnClick="clearButton_Click" BackColor="#33CC33" />
</div>
<div>
<asp:Label ID="submitLabel1" runat="server" Text="Thank you for your Request." Visible="False" ForeColor="Green"></asp:Label>
</div>
<div>
<asp:Label ID="submitLabel2" runat="server" EnableViewState="False" Text="We will get back to you within 24 hours." Visible="False" ForeColor="Green"></asp:Label>
</div>
</div>
</form>
</body>
</html>
答案 0 :(得分：0)
其中一个属性正在接收'NULL'，并且在将此值插入数据库时，您的表结构不允许'NULL'。
因此，如果要在表中存储“NULL”，请确保在表结构中允许NULL（表设计）。
您可以使用代码的“逐行执行”来检查它（使用断点）。