C# 该项目编译得非常完美，但我遇到了一个未处理的异常，不知道为什么
我得到一个未处理的异常，它说：C# 该项目编译得非常完美，但我遇到了一个未处理的异常，不知道为什么,c#,winforms,C#,Winforms,我得到一个未处理的异常，它说： System.NullReferenceException: Object reference not set to an instance of an object. at Eagle_Eye_Class_Finder.GetSchedule.GetDataFromNumber(String ID) in C:\Users\Joshua Banks\Desktop\EET Project\Eagle Eye Class Finder\GetSchedule.cs
System.NullReferenceException: Object reference not set to an instance of an object.
at Eagle_Eye_Class_Finder.GetSchedule.GetDataFromNumber(String ID) in C:\Users\Joshua Banks\Desktop\EET Project\Eagle Eye Class Finder\GetSchedule.cs:line 24
at Eagle_Eye_Class_Finder.Form1.button2_Click(Object sender, EventArgs e) in C:\Users\Joshua Banks\Desktop\EET Project\Eagle Eye Class Finder\Form1.cs:line 196
at System.Windows.Forms.Control.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnClick(EventArgs e)
at System.Windows.Forms.Button.PerformClick()
at System.Windows.Forms.Form.ProcessDialogKey(Keys keyData)
at System.Windows.Forms.Control.ProcessDialogKey(Keys keyData)
at System.Windows.Forms.TextBoxBase.ProcessDialogKey(Keys keyData)
at System.Windows.Forms.Control.PreProcessMessage(Message& msg)
at System.Windows.Forms.Control.PreProcessControlMessageInternal(Control target, Message& msg)
at System.Windows.Forms.Application.ThreadContext.PreTranslateMessage(MSG& msg)
using System;
using System.IO;
using System.Data;
using System.Text;
using System.Drawing;
using System.Data.OleDb;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Drawing.Printing;
using System.Collections.Generic;
namespace Eagle_Eye_Class_Finder
{
public class GetSchedule
{
public string GetDataFromNumber(string ID)
{
IDnumber[] IDnumbers = new IDnumber[3];
foreach (IDnumber IDCandidateMatch in IDnumbers)
{
if (IDCandidateMatch.ID == ID)
{
StringBuilder myData = new StringBuilder();
myData.AppendLine(IDCandidateMatch.Name);
myData.AppendLine(": ");
myData.AppendLine(IDCandidateMatch.ID);
myData.AppendLine(IDCandidateMatch.year);
myData.AppendLine(IDCandidateMatch.class1);
myData.AppendLine(IDCandidateMatch.class2);
myData.AppendLine(IDCandidateMatch.class3);
myData.AppendLine(IDCandidateMatch.class4);
//return myData;
return myData.ToString();
}
}
return "";
}
public GetSchedule()
{
IDnumber[] IDnumbers = new IDnumber[3];
IDnumbers[0] = new IDnumber() { Name = "Joshua Banks", ID = "900456317", year = "Senior", class1 = "TEET 4090", class2 = "TEET 3020", class3 = "TEET 3090", class4 = "TEET 4290" };
IDnumbers[1] = new IDnumber() { Name = "Sean Ward", ID = "900456318", year = "Junior", class1 = "ENGNR 4090", class2 = "ENGNR 3020", class3 = "ENGNR 3090", class4 = "ENGNR 4290" };
IDnumbers[2] = new IDnumber() { Name = "Terrell Johnson", ID = "900456319", year = "Sophomore", class1 = "BUS 4090", class2 = "BUS 3020", class3 = "BUS 3090", class4 = "BUS 4290" };
}
public class IDnumber
{
public string Name { get; set; }
public string ID { get; set; }
public string year { get; set; }
public string class1 { get; set; }
public string class2 { get; set; }
public string class3 { get; set; }
public string class4 { get; set; }
public static void ProcessNumber(IDnumber myNum)
{
StringBuilder myData = new StringBuilder();
myData.AppendLine(myNum.Name);
myData.AppendLine(": ");
myData.AppendLine(myNum.ID);
myData.AppendLine(myNum.year);
myData.AppendLine(myNum.class1);
myData.AppendLine(myNum.class2);
myData.AppendLine(myNum.class3);
myData.AppendLine(myNum.class4);
MessageBox.Show(myData.ToString());
}
}
}
}
using System;
using System.IO;
using System.Data;
using System.Text;
using System.Drawing;
using System.Data.OleDb;
using System.Collections;
using System.Windows.Forms;
using System.ComponentModel;
using System.Drawing.Printing;
using System.Collections.Generic;
namespace Eagle_Eye_Class_Finder
{
/// This form is the entry form, it is the first form the user will see when the app is run.
///
public class Form1 : System.Windows.Forms.Form
{
private System.Windows.Forms.TextBox textBox1;
private System.Windows.Forms.ProgressBar progressBar1;
private System.Windows.Forms.PictureBox pictureBox1;
private System.Windows.Forms.Button button2;
private System.Windows.Forms.DateTimePicker dateTimePicker1;
private IContainer components;
private Timer timer1;
private BindingSource form1BindingSource;
public static Form Mainform = null;
// creates new instance of second form
YOURCLASSSCHEDULE SecondForm = new YOURCLASSSCHEDULE();
public Form1()
{
InitializeComponent();
// TODO: Add any constructor code after InitializeComponent call
}
/// Clean up any resources being used.
protected override void Dispose(bool disposing)
{
if (disposing)
{
if (components != null)
{
components.Dispose();
}
}
base.Dispose(disposing);
}
#region Windows Form Designer generated code
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
this.components = new System.ComponentModel.Container();
System.ComponentModel.ComponentResourceManager resources = new System.ComponentModel.ComponentResourceManager(typeof(Form1));
this.textBox1 = new System.Windows.Forms.TextBox();
this.progressBar1 = new System.Windows.Forms.ProgressBar();
this.pictureBox1 = new System.Windows.Forms.PictureBox();
this.button2 = new System.Windows.Forms.Button();
this.dateTimePicker1 = new System.Windows.Forms.DateTimePicker();
this.timer1 = new System.Windows.Forms.Timer(this.components);
this.form1BindingSource = new System.Windows.Forms.BindingSource(this.components);
((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).BeginInit();
((System.ComponentModel.ISupportInitialize)(this.form1BindingSource)).BeginInit();
this.SuspendLayout();
//
// textBox1
//
this.textBox1.BackColor = System.Drawing.SystemColors.ActiveCaption;
this.textBox1.DataBindings.Add(new System.Windows.Forms.Binding("Text", this.form1BindingSource, "Text", true, System.Windows.Forms.DataSourceUpdateMode.OnValidation, null, "900456317"));
this.textBox1.Location = new System.Drawing.Point(328, 280);
this.textBox1.Name = "textBox1";
this.textBox1.Size = new System.Drawing.Size(208, 20);
this.textBox1.TabIndex = 2;
this.textBox1.TextChanged += new System.EventHandler(this.textBox1_TextChanged);
//
// progressBar1
//
this.progressBar1.Location = new System.Drawing.Point(258, 410);
this.progressBar1.MarqueeAnimationSpeed = 10;
this.progressBar1.Name = "progressBar1";
this.progressBar1.Size = new System.Drawing.Size(344, 8);
this.progressBar1.TabIndex = 3;
this.progressBar1.Click += new System.EventHandler(this.progressBar1_Click);
//
// pictureBox1
//
this.pictureBox1.BackColor = System.Drawing.SystemColors.ControlLightLight;
this.pictureBox1.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
this.pictureBox1.Image = ((System.Drawing.Image)(resources.GetObject("pictureBox1.Image")));
this.pictureBox1.Location = new System.Drawing.Point(680, 400);
this.pictureBox1.Name = "pictureBox1";
this.pictureBox1.Size = new System.Drawing.Size(120, 112);
this.pictureBox1.TabIndex = 4;
this.pictureBox1.TabStop = false;
this.pictureBox1.Click += new System.EventHandler(this.pictureBox1_Click);
//
// button2
//
this.button2.Font = new System.Drawing.Font("Mistral", 15.75F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
this.button2.Image = ((System.Drawing.Image)(resources.GetObject("button2.Image")));
this.button2.Location = new System.Drawing.Point(699, 442);
this.button2.Name = "button2";
this.button2.Size = new System.Drawing.Size(78, 28);
this.button2.TabIndex = 5;
this.button2.Text = "OK";
this.button2.Click += new System.EventHandler(this.button2_Click);
//
// dateTimePicker1
//
this.dateTimePicker1.Location = new System.Drawing.Point(336, 104);
this.dateTimePicker1.Name = "dateTimePicker1";
this.dateTimePicker1.Size = new System.Drawing.Size(200, 20);
this.dateTimePicker1.TabIndex = 6;
this.dateTimePicker1.ValueChanged += new System.EventHandler(this.dateTimePicker1_ValueChanged);
//
// timer1
//
this.timer1.Tick += new System.EventHandler(this.timer1_Tick);
//
// form1BindingSource
//
this.form1BindingSource.DataSource = typeof(Eagle_Eye_Class_Finder.Form1);
//
// Form1
//
this.AcceptButton = this.button2;
this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
this.BackgroundImage = ((System.Drawing.Image)(resources.GetObject("$this.BackgroundImage")));
this.BackgroundImageLayout = System.Windows.Forms.ImageLayout.Stretch;
this.ClientSize = new System.Drawing.Size(856, 556);
this.Controls.Add(this.dateTimePicker1);
this.Controls.Add(this.button2);
this.Controls.Add(this.pictureBox1);
this.Controls.Add(this.progressBar1);
this.Controls.Add(this.textBox1);
this.Name = "Form1";
this.Text = "Eagle Eye Class Finder";
this.Load += new System.EventHandler(this.Form1_Load);
((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).EndInit();
((System.ComponentModel.ISupportInitialize)(this.form1BindingSource)).EndInit();
this.ResumeLayout(false);
this.PerformLayout();
}
#endregion
/// The main entry point for the application.
[STAThread]
static void Main()
{
Application.Run(new Form1());
}
public void Form1_Load(object sender, System.EventArgs e)
{
}
public void textBox1_TextChanged(object sender, System.EventArgs e)
{
//allows only numbers to be entered in textbox
string Str = textBox1.Text.Trim();
double Num;
bool isNum = double.TryParse(Str, out Num);
if (isNum)
Console.ReadLine();
else
MessageBox.Show("Enter A Valid ID Number!");
}
public void button2_Click(object sender, System.EventArgs e)
{
string text = textBox1.Text;
Mainform = this;
this.Hide();
GetSchedule myScheduleFinder = new GetSchedule();
string result = myScheduleFinder.GetDataFromNumber(text);
if (!string.IsNullOrEmpty(result))
{
MessageBox.Show(result);
}
else
{
MessageBox.Show("Enter A Valid ID Number!");
}
}
public void dateTimePicker1_ValueChanged(object sender, System.EventArgs e)
{
}
public void pictureBox1_Click(object sender, System.EventArgs e)
{
}
public void progressBar1_Click(object sender, EventArgs e)
{
//this.progressBar1 = new System.progressBar1();
//progressBar1.Maximum = 200;
//progressBar1.Minimum = 0;
//progressBar1.Step = 20;
}
private void timer1_Tick(object sender, EventArgs e)
{
//if (progressBar1.Value >= 200 )
//{
//progressBar1.Value = 0;
//}
//return;
//}
//progressBar1.Value != 20;
}
}
}
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
namespace Eagle_Eye_Class_Finder
{
/// <summary>
/// Summary description for Form2.
/// </summary>
public class YOURCLASSSCHEDULE : System.Windows.Forms.Form
{
public System.Windows.Forms.LinkLabel linkLabel1;
public System.Windows.Forms.LinkLabel linkLabel2;
public System.Windows.Forms.LinkLabel linkLabel3;
public System.Windows.Forms.LinkLabel linkLabel4;
private Button button1;
/// Required designer variable.
public System.ComponentModel.Container components = null;
public YOURCLASSSCHEDULE()
{
//
InitializeComponent();
// TODO: Add any constructor code after InitializeComponent call
}
/// Clean up any resources being used.
protected override void Dispose(bool disposing)
{
if (disposing)
{
if (components != null)
{
components.Dispose();
}
}
base.Dispose(disposing);
}
#region Windows Form Designer generated code
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
System.ComponentModel.ComponentResourceManager resources = new System.ComponentModel.ComponentResourceManager(typeof(YOURCLASSSCHEDULE));
this.linkLabel1 = new System.Windows.Forms.LinkLabel();
this.linkLabel2 = new System.Windows.Forms.LinkLabel();
this.linkLabel3 = new System.Windows.Forms.LinkLabel();
this.linkLabel4 = new System.Windows.Forms.LinkLabel();
this.button1 = new System.Windows.Forms.Button();
this.SuspendLayout();
//
// linkLabel1
//
this.linkLabel1.BackColor = System.Drawing.SystemColors.ActiveCaption;
this.linkLabel1.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
this.linkLabel1.Font = new System.Drawing.Font("Times New Roman", 14.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
this.linkLabel1.LinkArea = new System.Windows.Forms.LinkArea(0, 7);
this.linkLabel1.LinkBehavior = System.Windows.Forms.LinkBehavior.HoverUnderline;
this.linkLabel1.Location = new System.Drawing.Point(41, 123);
this.linkLabel1.Name = "linkLabel1";
this.linkLabel1.Size = new System.Drawing.Size(288, 32);
this.linkLabel1.TabIndex = 1;
this.linkLabel1.TabStop = true;
this.linkLabel1.Text = "Class 1";
this.linkLabel1.TextAlign = System.Drawing.ContentAlignment.MiddleCenter;
this.linkLabel1.LinkClicked += new System.Windows.Forms.LinkLabelLinkClickedEventHandler(this.linkLabel1_LinkClicked);
//
// linkLabel2
//
this.linkLabel2.BackColor = System.Drawing.SystemColors.ActiveCaption;
this.linkLabel2.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
this.linkLabel2.Font = new System.Drawing.Font("Times New Roman", 14.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
this.linkLabel2.LinkBehavior = System.Windows.Forms.LinkBehavior.HoverUnderline;
this.linkLabel2.Location = new System.Drawing.Point(467, 123);
this.linkLabel2.Name = "linkLabel2";
this.linkLabel2.Size = new System.Drawing.Size(288, 32);
this.linkLabel2.TabIndex = 2;
this.linkLabel2.TabStop = true;
this.linkLabel2.Text = "Class 2";
this.linkLabel2.TextAlign = System.Drawing.ContentAlignment.MiddleCenter;
this.linkLabel2.VisitedLinkColor = System.Drawing.Color.Navy;
this.linkLabel2.LinkClicked += new System.Windows.Forms.LinkLabelLinkClickedEventHandler(this.linkLabel2_LinkClicked);
//
// linkLabel3
//
this.linkLabel3.BackColor = System.Drawing.SystemColors.ActiveCaption;
this.linkLabel3.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
this.linkLabel3.Font = new System.Drawing.Font("Times New Roman", 14.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
this.linkLabel3.LinkBehavior = System.Windows.Forms.LinkBehavior.HoverUnderline;
this.linkLabel3.Location = new System.Drawing.Point(41, 311);
this.linkLabel3.Name = "linkLabel3";
this.linkLabel3.Size = new System.Drawing.Size(288, 32);
this.linkLabel3.TabIndex = 3;
this.linkLabel3.TabStop = true;
this.linkLabel3.Text = "Class 3";
this.linkLabel3.TextAlign = System.Drawing.ContentAlignment.MiddleCenter;
this.linkLabel3.LinkClicked += new System.Windows.Forms.LinkLabelLinkClickedEventHandler(this.linkLabel3_LinkClicked);
//
// linkLabel4
//
this.linkLabel4.BackColor = System.Drawing.SystemColors.ActiveCaption;
this.linkLabel4.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
this.linkLabel4.Font = new System.Drawing.Font("Times New Roman", 14.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
this.linkLabel4.LinkBehavior = System.Windows.Forms.LinkBehavior.HoverUnderline;
this.linkLabel4.Location = new System.Drawing.Point(467, 311);
this.linkLabel4.Name = "linkLabel4";
this.linkLabel4.Size = new System.Drawing.Size(288, 32);
this.linkLabel4.TabIndex = 4;
this.linkLabel4.TabStop = true;
this.linkLabel4.Text = "Class 4";
this.linkLabel4.TextAlign = System.Drawing.ContentAlignment.MiddleCenter;
this.linkLabel4.LinkClicked += new System.Windows.Forms.LinkLabelLinkClickedEventHandler(this.linkLabel4_LinkClicked);
//
// button1
//
this.button1.BackColor = System.Drawing.SystemColors.ActiveCaptionText;
this.button1.FlatAppearance.BorderColor = System.Drawing.Color.FromArgb(((int)(((byte)(0)))), ((int)(((byte)(0)))), ((int)(((byte)(64)))));
this.button1.FlatStyle = System.Windows.Forms.FlatStyle.Popup;
this.button1.Font = new System.Drawing.Font("Pristina", 12F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
this.button1.ForeColor = System.Drawing.SystemColors.ActiveCaption;
this.button1.ImageAlign = System.Drawing.ContentAlignment.TopCenter;
this.button1.Location = new System.Drawing.Point(358, 206);
this.button1.Name = "button1";
this.button1.Size = new System.Drawing.Size(101, 25);
this.button1.TabIndex = 5;
this.button1.Text = "Go Back";
this.button1.UseVisualStyleBackColor = false;
this.button1.Click += new System.EventHandler(this.button1_Click);
//
// YOURCLASSSCHEDULE
//
this.AutoScaleBaseSize = new System.Drawing.Size(6, 15);
this.BackgroundImage = ((System.Drawing.Image)(resources.GetObject("$this.BackgroundImage")));
this.BackgroundImageLayout = System.Windows.Forms.ImageLayout.Stretch;
this.ClientSize = new System.Drawing.Size(790, 482);
this.Controls.Add(this.button1);
this.Controls.Add(this.linkLabel4);
this.Controls.Add(this.linkLabel3);
this.Controls.Add(this.linkLabel2);
this.Controls.Add(this.linkLabel1);
this.Font = new System.Drawing.Font("OldDreadfulNo7 BT", 8.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
this.Name = "YOURCLASSSCHEDULE";
this.Text = "Your Classes";
this.Load += new System.EventHandler(this.Form2_Load);
this.ResumeLayout(false);
}
#endregion
public void Form2_Load(object sender, System.EventArgs e)
{
// if (text == "900456317")
// {
//}
}
public void linkLabel1_LinkClicked(object sender, System.Windows.Forms.LinkLabelLinkClickedEventArgs e)
{
System.Diagnostics.Process.Start("http://www.georgiasouthern.edu/map/");
}
private void linkLabel2_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e)
{
System.Diagnostics.Process.Start("http://www.georgiasouthern.edu/map/");
}
private void linkLabel3_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e)
{
System.Diagnostics.Process.Start("http://www.georgiasouthern.edu/map/");
}
private void linkLabel4_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e)
{
System.Diagnostics.Process.Start("http://www.georgiasouthern.edu/map/");
}
private void button1_Click(object sender, EventArgs e)
{
Form1 form1 = new Form1();
form1.Show();
this.Hide();
}
}
}
完美编译与异常无关。我建议查看异常上的stacktrace，尝试找到发生错误的行，然后从那里开始 看起来GetSchedule.cs的第24行是一个很好的起点 问题出在这个if语句上：
IDnumber[] IDnumbers = new IDnumber[3];
foreach (IDnumber IDCandidateMatch in IDnumbers)
{
if (IDCandidateMatch.ID == ID)
您创建了包含三个元素的数组，但所有元素都为空。循环遍历它们时，对IDCandidateMatch.ID的引用将生成NullReferenceException。您正在创建两个不同的数组，一个在构造函数中，另一个在方法中。如果你移动线 IDnumber[]IDnumbers=新的IDnumber[3]；
在方法之外，删除构造器中相同的方法，它应该可以工作Hmm-你的行扫描比我的更准确；我让人在那一行后面钉上两行字。老兄，我讨厌你在痛苦地写下深刻的回应时，却发现有人在你后面写了两行字；我试着识别身份证号码，如果没有那条线，它会说身份证号码不存在@Michael Shimins，@OJ，@JB，我重新格式化了所有代码，使其在so中正确显示。这也使得我们能够看到哪一行是24-是的，先生，这就是问题所在，非常感谢，我对C有点陌生，但是这个网站在学习这门语言方面帮了我很大的忙！！