我的C＃Windows窗体应用程序出现问题。我有一个格式的文本文件 - LastName，FirstName，MiddleName，DateOfEnrolment，Gender如下：
布罗格斯，乔，约翰，2015/1月4日，男
文本文件中有10行。
我想读取文本文件，拆分每一行并将每个元素放入一个数组中。然后将每个元素放入其自己的标签中。有一个名为open的按钮用于打开文本文件，然后有一个名为first的按钮，用于显示各个标签中第一行的元素。有一个名为previous的按钮转到上一行，下一个按钮转到下一行，最后一个按钮转到最后一行，再次显示标签中所选行的元素.v下面的代码是我已经有的但是btnFirst_Click全部显示为红色。
请帮忙！
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO;
namespace Assignment1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
public class SR
{
public string lastName;
public string firstName;
public string middleName;
public string date;
public string gender;
}
private void btnOpen_Click(object sender, EventArgs e)
{
List<SR> studentRecords = new List<SR>();
string file_name = (@"C:\Users\StudentRecords.txt");
StreamReader objReader = new StreamReader(file_name);
objReader = new StreamReader(file_name);
int counter = 0;
string line;
while ((line = objReader.ReadLine()) != null)
{
listBox.Items.Add(line);
counter++;
}
{
while (objReader.Peek() >= 0)
{
string str;
string[] strArray;
str = objReader.ReadLine();
strArray = str.Split(',');
SR currentSR = new SR();
currentSR.lastName = strArray[0];
currentSR.firstName = strArray[1];
currentSR.middleName = strArray[2];
currentSR.date = strArray[3];
currentSR.gender = strArray[4];
studentRecords.Add(currentSR);
}
}
objReader.Close();
}
private void btnFirst_Click(object sender, EventArgs e)
{
lblFN.Text = strArray[1];
lblMN.Text = strArray[2];
lblLN.Text = strArray[0];
lblDoE.Text = strArray[3];
lblGen.Text = strArray[4];
}
答案 0 :(得分：0)
您的strArray是在btnOpen_Click方法的循环中定义的。因此，尝试从btnFirst_Click访问它将无效。您需要在方法之外移动strArray的声明，以便在两者中都可以访问它。
尝试将其移至类定义的顶部，如下所示：
namespace Assignment1
{
public partial class Form1 : Form
{
private string[] strArray; // <---------- here is your array
public Form1()
{
InitializeComponent();
}
...
然后，您可以从btnOpen_Click和btnFirst_Click访问该数组。
答案 1 :(得分：0)
首先，真的很需要嵌套类，所以.. （使用完整的类名，不需要懒惰，并且不要使用公共字段，使用属性（大写））。
public class StudentRecord
{
public string LastName { get; set;}
public string FirstName { get; set;}
public string MiddleName { get; set;}
public string Date { get; set;}
public string Gender { get; set;}
}
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
// ....
}
其次，避免使用数组（恕我直言）：
public partial class Form1 : Form
{
// initialize list to zero, we'll reset everytime
// we load students. Also a null list will
// throw an error below the way I have it coded.
private List<StudentRecord> _studentRecords = new List<StudentRecord>(0);
// ..
}
避免在btnOpen_Click方法中实际放置逻辑：
private void btnOpen_Click(object sender, EventArgs e)
{
LoadStudentRecords();
}
阅读文件的简便方法：
private void LoadStudentRecords()
{
// reset the list to empty, so we don't always append to existing
_studentRecords = new List<StudentRecord>();
string file_name = (@"C:\Users\StudentRecords.txt");
var lines = File.ReadAllLines(file_name).ToList();
foreach(var line in lines)
{
var studentRecord = ParseStudentRecordLine(line);
if (studentRecord != null)
{
_studentRecords.Add(studentRecord);
}
}
}
将逻辑分离为逻辑方法：
public StudentRecord ParseStudentRecordLine(string line)
{
SR result = null;
// error check line, don't want to blow up
if (!string.IsNullOrWhiteSpace(line))
{
var values = line.Split(',');
// error values length, don't want to blow up
if (values.Length == 5) // or > 4
{
var result = new StudentRecord();
result.lastName = values [0];
result.firstName = values [1];
result.middleName = values [2];
result.date = values [3];
result.gender = values [4];
}
}
return result;
}
最后分配：
private void ShowStudent(StudentRecord studentRecord)
{
// what if we haven't loaded student records
// and someone tried to show one?
if (studentRecord != null)
{
lblFN.Text = studentRecord.FirstName;
lblMN.Text = studentRecord.MiddleName;
lblLN.Text = studentRecord.LastName;
lblDoE.Text = studentRecord.Date;
lblGen.Text = studentRecord.Gender;
_currentStudentRecordIndex = _studentRecords.IndexOf(studentRecord);
}
else
{
// Show error msg "No students to show, maybe load students first"
}
}
有一个名为previous的按钮转到上一行，下一行按钮转到下一行，最后一个按钮转到最后一行，
所以你想保留当前元素的索引。将索引添加到表单中：
public partial class Form1 : Form
{
private List<StudentRecord> _studentRecords = new List<StudentRecord>(0);
private int _currentStudentRecordIndex = 0;
}
如果您加载或先按下，请确保将值重置为零。
private void LoadStudentRecords()
{
_currentStudentRecordIndex = 0;
_studentRecords = new List<StudentRecord>();
// ....
标准第一/上一个/下一个/最后一个逻辑：
（可以换一种方式，只是做一些Labda / Linq Fun的例子）。
private void btnFirst_Click(object sender, EventArgs e)
{
var firstStudent = _studentRecords.FirstOrDefault();
ShowStudent(firstStudent);
}
private void btnLast_Click(object sender, EventArgs e)
{
var count = _studentRecords.Count;
if (count > 0)
{
var studentRecord = _studentRecords.ElementAt(count-1);
ShowStudent(studentRecord );
}
}
private void btnPrevious_Click(object sender, EventArgs e)
{
var studentRecordIndex = _currentStudentRecordIndex - 1;
if (studentRecordIndex > -1)
{
var studentRecord = _studentRecords.ElementAt(studentRecordIndex );
ShowStudent(studentRecord );
}
}
private void btnNext_Click(object sender, EventArgs e)
{
// Should be able to do this based on previous logic
}
备注
这远非完美，但我希望它能解释你在寻找什么。
答案 2 :(得分：0)
我可能正在为你做任务，大声笑但是这会得到你所追求的结果：
class Program
{
// Contains the elements of an line after it's been parsed.
static string[] array;
static void Main(string[] args)
{
// Read the lines of a file into a list of strings. Iterate through each
// line and create an array of elements by parsing (splitting) the line by a delimiter (eg. a comma).
// Then display what's now contained within the array of strings.
var lines = ReadFile("dummy.txt");
foreach (string line in lines)
{
array = CreateArray(line);
Display();
}
// Prevent the console window from closing.
Console.ReadLine();
}
// Reads a file and returns an array of strings.
static List<string> ReadFile(string fileName)
{
var lines = new List<string>();
using (var file = new StreamReader(fileName))
{
string line = string.Empty;
while ((line = file.ReadLine()) != null)
{
lines.Add(line);
}
}
return lines;
}
// Create an array of string elements from a comma delimited string.
static string[] CreateArray(string line)
{
return line.Split(',');
}
// Display the results to the console window for demonstration.
static void Display()
{
foreach (string item in array)
{
Console.WriteLine(item);
}
Console.WriteLine();
}
}
文本文件中包含的示例如下：
Bloggs,Joe,John,2015/01/04,M
Jones,Janet,Gillian,2015/01/04,F
Jenfrey,Jill,April,2015/01/04,F
Drogger,Jeff,Jimmy,2015/01/04,M
结果将是：
Bloggs
Joe
John
2015/01/04
M
Jones
Janet
Gillian
2015/01/04
F
Jenfrey
Jill
April
2015/01/04
F
Drogger
Jeff
Jimmy
2015/01/04
M
或者，根据您的业务需求，您可以使用以下解决方案生成学生记录对象列表：
class Program
{
static int _recordIndex;
static List<StudentRecord> _studentRecords;
static void Main(string[] args)
{
// Initialize a list of student records and set the record index to the index of the first record.
_studentRecords = new List<StudentRecord>();
_recordIndex = 0;
// Read the lines of a file into a list of strings. Iterate through each
// line and create a list of student records of elements by parsing (splitting) the line by a delimiter (eg. a comma).
// Then display what's now contained within the list of records.
var lines = ReadFile("dummy.txt");
foreach (string line in lines)
{
_studentRecords.Add(CreateStudentResult(line));
}
Display();
// Prevent the console window from closing.
Console.ReadLine();
}
// Reads a file and returns an array of strings.
static List<string> ReadFile(string fileName)
{
var lines = new List<string>();
using (var file = new StreamReader(fileName))
{
string line = string.Empty;
while ((line = file.ReadLine()) != null)
{
lines.Add(line);
}
}
return lines;
}
// Get the next student record in the list of records
static StudentRecord GetNext()
{
// Check to see if there are any records, if not... don't bother running the rest of the method.
if (_studentRecords.Count == 0)
return null;
// If we are on the index of the last record in the list, set the record index back to the first record.
if (_recordIndex == _studentRecords.Count - 1)
{
_recordIndex = 0;
}
// Otherwise, simply increment the record index by 1.
else
{
_recordIndex++;
}
// Return the record at the the new index.
return _studentRecords[_recordIndex];
}
static StudentRecord GetPrevious()
{
// Check to see if there are any records, if not... don't bother running the rest of the method.
if (_studentRecords.Count == 0)
return null;
// If we are on the index of the first record in the list, set the record index to the last record.
if (_recordIndex == 0)
{
_recordIndex = _studentRecords.Count - 1;
}
// Otherwise, simply deincrement the record index by 1.
else
{
_recordIndex--;
}
// Return the record at the the new index.
return _studentRecords[_recordIndex];
}
// Create a StudentResult object containing the string elements from a comma delimited string.
static StudentRecord CreateStudentResult(string line)
{
var parts = line.Split(',');
return new StudentRecord(parts[0], parts[1], parts[2], parts[3], parts[4]);
}
// Display the results to the console window for demonstration.
static void Display()
{
// Display a list of all the records
Console.WriteLine("Student records:\n----------------");
foreach (var record in _studentRecords)
{
Console.WriteLine(record.ToString());
Console.WriteLine();
}
// Display the first record in the list
Console.WriteLine("First record is:\n----------------");
Console.WriteLine(_studentRecords.First().ToString());
Console.WriteLine();
// Display the last record in the list.
Console.WriteLine("Last record is:\n----------------");
Console.WriteLine(_studentRecords.Last().ToString());
Console.WriteLine();
// Display the next record in the list
Console.WriteLine("Next record is:\n----------------");
Console.WriteLine(GetNext().ToString());
Console.WriteLine();
// Display the last record in the list.
Console.WriteLine("Previous record is:\n----------------");
Console.WriteLine(GetPrevious().ToString());
Console.WriteLine();
}
// A record object used to store the elements of parsed string.
public class StudentRecord
{
public string LastName { get; set; }
public string FirstName { get; set; }
public string MiddleName { get; set; }
public string Date { get; set; }
public string Gender { get; set; }
// Default constructor
public StudentRecord()
{
}
// Overloaded constructor that accepts the parts of a parsed or split string.
public StudentRecord(string lastName, string firstName, string middleName, string date, string gender)
{
this.LastName = lastName;
this.FirstName = firstName;
this.MiddleName = middleName;
this.Date = date;
this.Gender = gender;
}
// Overrided ToString method which returns a string of property values.
public override string ToString()
{
return string.Format(
"Last name: {0}\nFirst name: {1}\nMiddle name: {2}\nDate {3}\nGender: {4}",
this.LastName, this.FirstName, this.MiddleName, this.Date, this.Gender);
}
}
}
以上代码的结果如下：
Student records:
----------------
Last name: Bloggs
First name: Joe
Middle name: John
Date 2015/01/04
Gender: M
Last name: Jones
First name: Janet
Middle name: Gillian
Date 2015/01/04
Gender: F
Last name: Jenfrey
First name: Jill
Middle name: April
Date 2015/01/04
Gender: F
Last name: Drogger
First name: Jeff
Middle name: Jimmy
Date 2015/01/04
Gender: M
First record is:
----------------
Last name: Bloggs
First name: Joe
Middle name: John
Date 2015/01/04
Gender: M
Last record is:
----------------
Last name: Drogger
First name: Jeff
Middle name: Jimmy
Date 2015/01/04
Gender: M
Next record is:
----------------
Last name: Jones
First name: Janet
Middle name: Gillian
Date 2015/01/04
Gender: F
Previous record is:
----------------
Last name: Bloggs
First name: Joe
Middle name: John
Date 2015/01/04
Gender: M