Question

我不确定为什么我的文件没有在我的C＃程序中读取。当我运行它时，它只在文本框中给出一个0，并且不列出任何名称。我想知道它是否与其他东西有问题，它正在正确读取文件。感谢大家的帮助！

以下是调用该文件的CustomerDA类，我不确定它是否正确：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;


namespace CustomerList
{
public static class CustomerDA
{
    private const string dir = @"Z:\Desktop\Windows 7 Files\C#.net\CustomerList\CustomerList";
    private const string path = dir + "CustomerDat.txt";

    public static List<Customer> GetAllCustomers()
    {
        if (!Directory.Exists(dir))
            Directory.CreateDirectory(dir);

        StreamReader textIn =
            new StreamReader(
                new FileStream(path, FileMode.Open, FileAccess.Read));

        List<Customer> custList = new List<Customer>(); // this create the list to add the Customers to.
        while (textIn.Peek() != -1)
        {
            string row = textIn.ReadLine();
            string[] columns = row.Split(',');
            Customer customer = new Customer();
            customer.Name = columns[0];
            customer.Email = columns[1];
            customer.CreditRating = Convert.ToInt16(columns[2]);
            customer.City = columns[3];
            customer.Zip = columns[4];
        }

        textIn.Close();

        // use the method to read found in the book as an example on page 677
        // The file to read can be found on Moodle CustomerDat.txt
        // I also placed a copy in this project.


        //once all of the Customers have been read into the List return the list
        return custList;
    }
}
}

这是Form1.cs，我不确定我是否正确调用它。对我来说一切似乎都是正确的：

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;

namespace CustomerList
{
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    List<Customer> ourCustomers = new List<Customer>();

    private void Form1_Load(object sender, EventArgs e)
    {
        // call the CustomerDa Class and read all of the Customers from the file and return the list back here
        ourCustomers = CustomerDA.GetAllCustomers();
    }

    private void btnShowGood_Click(object sender, EventArgs e)
    {
        int numGoodCustomers = 0;

        // loop through all of the customers returned from the file
        foreach (Customer cust in ourCustomers)
        {
            // see if the customer has a rating > 8
            if(cust.CreditRating > 8)
            {
                // add the name to the listbox
                lstGoodCustomers.Items.Add(cust.Name);
                // add one to the count of good customers
                numGoodCustomers ++;

            }

        }

        // Update the form with the number of good Customers
        txtNumGoodCustomers.Text = numGoodCustomers.ToString();
    }
}
}

Answer 1

您在阅读时从不添加到列表中，因此它始终为空。将custList.Add(customer)添加到循环的末尾。

private const string dir = @"Z:\Desktop\Windows 7 Files\C#.net\CustomerList\CustomerList";
private const string path = Path.Combine(dir, "CustomerDat.txt");

List<Customer> custList = new List<Customer>(); // this create the list to add the Customers to.
while (textIn.Peek() != -1)
{
   string row = textIn.ReadLine();
   string[] columns = row.Split(',');
   Customer customer = new Customer();
   customer.Name = columns[0];
   customer.Email = columns[1];
   customer.CreditRating = Convert.ToInt16(columns[2]);
   customer.City = columns[3];
   customer.Zip = columns[4];
   custList.Add(customer); //This was missing
}

正如@Gusman所说（添加到我的完整性答案中），您需要使用Path.Combine代替＆＃39; +＆＃39;同样，你的路径也是无效的。

Answer 2

好的，很简单，使用ALWAYS Path.Combine连接两个路径元素。

我为什么这么说？

看，你有dir = @＆＃34; Z：\ Desktop \ Windows 7 Files \ C＃.net \ CustomerList \ CustomerList＆＃34;和path = dir +＆＃34; CustomerDat.txt＆＃34;，所以路径是@＆＃34; Z：\ Desktop \ Windows 7 Files \ C＃.net \ CustomerList \ CustomerListCustomerDat.txt＆＃34;。

你错过了＆＃34; \＆＃34;，使用Path.Combine可以避免这些问题。

为什么我的文件不是用C＃读取的？

2 个答案: