C#如何读取用户输入并将其添加到文本文件中？ [复制]

Question

我正在尝试制作一个 C# 应用程序，该应用程序可以从 .txt 文件读取和输出信息，然后允许用户在该文件末尾输入更多信息。我正在尝试以 CSV 格式编写文本文件，但在弄清楚如何添加到文件的底部时遇到了很多麻烦。似乎当我尝试时，它会覆盖文件的顶行。任何帮助表示赞赏。这是到目前为止的代码，对于任何令人困惑的行，我深表歉意——我一直在尝试许多不同的东西，我可以在网上找到它来尝试让它工作。

class Program
{
    static void Main(string[] args)
    {
        string UIName = "";
        string UIInvoice = "";
        string UIDue = "";
        string UIAmount = "";

        using (FileStream fs = new FileStream(@"C:\Accounts.txt", FileMode.Open))
        using (StreamReader sr = new StreamReader(fs))
        {
            string content = sr.ReadToEnd();
            string[] lines = content.Split(new string[] { Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries);

            int lineCount = 0;
            List<Account> accounts = new List<Account>();
            foreach (string line in lines)
            {
                string[] column = line.Split(',');
                if (lineCount != 0)
                {
                    Account account = new Account();
                    account.AccountName = column[0];
                    account.InvoiceDate = column[1];
                    account.DueDate = column[2];
                    account.AmountDue = column[3];
                    accounts.Add(account);
                }
                lineCount++;
            }
            Console.WriteLine(content);
        }
        using (FileStream fs = new FileStream(@"C:\Accounts.txt", FileMode.OpenOrCreate))
        using (StreamWriter sw = new StreamWriter(fs))
        {
            Account account = new Account();
            account.AccountName = UIName;
            account.InvoiceDate = UIInvoice;
            account.DueDate = UIDue;
            account.AmountDue = UIAmount;
            //accounts.Add(account);
            string fullText = (UIName + "," + UIInvoice + "," + UIDue + "," + UIAmount);
                    Console.WriteLine("Would you like to enter additional data?");


            Console.WriteLine("Please enter the Account Name: ");
            UIName = Console.ReadLine();
            Console.WriteLine("Please enter the Invoice Date: ");
            UIInvoice = Console.ReadLine();
            Console.WriteLine("Please enter the Due Date: ");
            UIDue = Console.ReadLine();
            Console.WriteLine("Please enter the AmountDue: ");
            UIAmount = Console.ReadLine();

            File.AppendAllText("C:/Accounts.txt", fullText + Environment.NewLine);//can't get this way working, even after switching "\"s to "/"s. It says that the file is being used by another process.

            Console.ReadLine();
        }
    }
}
}

单独的类：

public class Account
{
    public string AccountName { get; set; }
    public string InvoiceDate { get; set; }
    public string DueDate { get; set; }
    public string AmountDue { get; set; }

    public static string GetAccountCSV(Account account)
    {
        string returnValue = account.AccountName + "," + account.InvoiceDate + "," + account.DueDate + "," + account.AmountDue;
        return returnValue;
    }
}

.txt 文件说；

Account Name,Invoice Date,Due Date,Amount Due
Jane Doe,1/12/2017,2/12/2017,2000.00
Gonuts Inc,12/31/2017,2/28/2017,1566.50

Answer 1

您的代码有多个问题。

1. 您想将数据附加到文件的末尾，但您正在以OpenOrCreate 模式打开FileStream。 OpenOrCreate 模式将文件指针放在文件的开头。所以在那之后，无论你写入文件，它都会覆盖文件的现有内容。

2. 您正在打开FileStream 和StreamWriter，但不要使用它们将内容写入文件。而不是File.AppendAllText 你应该使用sw.WriteLine(fullText)。

另外，您将文件内容写入代码中的错误位置。

以下是去除上述所有问题的代码。

static void Main(string[] args)
    {
        string UIName = "";
        string UIInvoice = "";
        string UIDue = "";
        string UIAmount = "";
        var filePath = @"D:\Accounts.txt";
        using (FileStream fs = new FileStream(filePath, FileMode.OpenOrCreate))
        {
            using (StreamReader sr = new StreamReader(fs))
            {
                string content = sr.ReadToEnd();
                string[] lines = content.Split(new string[] {Environment.NewLine},
                    StringSplitOptions.RemoveEmptyEntries);

                int lineCount = 0;
                List<Account> accounts = new List<Account>();
                foreach (string line in lines)
                {
                    string[] column = line.Split(',');
                    if (lineCount != 0)
                    {
                        Account account = new Account();
                        account.AccountName = column[0];
                        account.InvoiceDate = column[1];
                        account.DueDate = column[2];
                        account.AmountDue = column[3];
                        accounts.Add(account);
                    }
                    lineCount++;
                }
                Console.WriteLine(content);
            }
        }

        using (FileStream fs = new FileStream(filePath, FileMode.Append))
        {
            using (StreamWriter sw = new StreamWriter(fs))
            {
                Account account = new Account();
                account.AccountName = UIName;
                account.InvoiceDate = UIInvoice;
                account.DueDate = UIDue;
                account.AmountDue = UIAmount;
                //accounts.Add(account);

                Console.WriteLine("Would you like to enter additional data?");
                Console.WriteLine("Please enter the Account Name: ");
                UIName = Console.ReadLine();
                Console.WriteLine("Please enter the Invoice Date: ");
                UIInvoice = Console.ReadLine();
                Console.WriteLine("Please enter the Due Date: ");
                UIDue = Console.ReadLine();
                Console.WriteLine("Please enter the AmountDue: ");
                UIAmount = Console.ReadLine();

                string fullText = (UIName + "," + UIInvoice + "," + UIDue + "," + UIAmount);

                sw.WriteLine(fullText);

                Console.ReadLine();
            }
        }
    }

Answer 2

你的代码有两个问题

1. 你必须以追加模式打开文件@ref chetan 评论
2. 您正在从用户输入读取之前创建全文字符串，因为它会将空字符串写入文本文件。

请在下面找到工作程序类文件

 class Program
{
    static void Main(string[] args)
    {
        string UIName = "";
        string UIInvoice = "";
        string UIDue = "";
        string UIAmount = "";

        using (FileStream fs = new FileStream(@"C:/Accounts.txt", FileMode.Open))
        using (StreamReader sr = new StreamReader(fs))
        {
            string content = sr.ReadToEnd();
            string[] lines = content.Split(new string[] { Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries);

            int lineCount = 0;
            List<Account> accounts = new List<Account>();
            foreach (string line in lines)
            {
                string[] column = line.Split(',');
                if (lineCount != 0)
                {
                    Account account = new Account();
                    account.AccountName = column[0];
                    account.InvoiceDate = column[1];
                    account.DueDate = column[2];
                    account.AmountDue = column[3];
                    accounts.Add(account);
                }
                lineCount++;
            }
            Console.WriteLine(content);
        }
        using (FileStream fs = new FileStream(@"C:/Accounts.txt", FileMode.Append))
        using (StreamWriter sw = new StreamWriter(fs))
        {
            Account account = new Account();
            account.AccountName = UIName;
            account.InvoiceDate = UIInvoice;
            account.DueDate = UIDue;
            account.AmountDue = UIAmount;
            //accounts.Add(account);
            Console.WriteLine("Would you like to enter additional data?");


            Console.WriteLine("Please enter the Account Name: ");
            UIName = Console.ReadLine();
            Console.WriteLine("Please enter the Invoice Date: ");
            UIInvoice = Console.ReadLine();
            Console.WriteLine("Please enter the Due Date: ");
            UIDue = Console.ReadLine();
            Console.WriteLine("Please enter the AmountDue: ");
            UIAmount = Console.ReadLine();
            string fullText = (UIName + "," + UIInvoice + "," + UIDue + "," + UIAmount);
            File.AppendAllText("C:/Accounts.txt", fullText + Environment.NewLine);//can't get this way working, even after switching "\"s to "/"s. It says that the file is being used by another process.
            Console.ReadLine();
        }
    }
}