Question

说明：

输入时：姓氏，名字， ID＃，班级和成绩。按＆＃34;确定＆＃34; 。按＆＃34;加载＆＃34; （输入的信息显示在下面的只读文本框中）。现在我再次输入，按＆＃34;确定＆＃34; 和＆＃34;再次加载＆＃34; （现在我看到两行信息）

以下是我的表单的图片：

会发生什么：

当我点击另存为时，将我的txt文件保存到某处并打开它。它将显示第一行的最后一个输入，以及secound上的空白（这似乎是第一个输入，但现在是空白）

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 StudentGrades
{
public partial class Form1 : Form
{
    static string status;
    public Form1()
    {
        InitializeComponent();

        writeButton.Enabled = false;
    }

    private void readButton_Click(object sender, EventArgs e)
    {
        using (StreamReader sr = 
            new StreamReader(@"C:\Users\User\Documents\Visual Studio 2017\Projects\StudentGrades\StudentGrades\TextFile.txt"))
        {
            textBoxReadGrades.AppendText(sr.ReadToEnd());
        }

    writeButton.Enabled = true;

    }

    private async void writeButton_Click(object sender, EventArgs e)
    {
        using (SaveFileDialog sfd = new SaveFileDialog() { Filter =
            "TextDocuments|*txt.", ValidateNames = true})
        {
            if (sfd.ShowDialog() == DialogResult.OK)
            {
                using (StreamWriter sw = new StreamWriter(sfd.FileName))
                {
                    await sw.WriteLineAsync(textBoxFirstName.Text +
                    "      " + textBoxLastName.Text +
                    "      " + textBoxID.Text +
                    "      " + textBoxClass.Text +
                    "      " + textBoxGrade.Text);

                    MessageBox.Show("You have successfully saved", "Message",
                        MessageBoxButtons.OK, MessageBoxIcon.Information);

                }
            }
        }
    }

    private void okButton_Click(object sender, EventArgs e)
    {
        using (StreamWriter sw = 
            new StreamWriter(@"C:\Users\User\Documents\Visual Studio 2017\Projects\StudentGrades\StudentGrades\TextFile.txt"))

            sw.WriteLine(textBoxFirstName.Text +
                 "      " + textBoxLastName.Text +
                 "      " + textBoxID.Text +
                 "      " + textBoxClass.Text +
                 "      " + textBoxGrade.Text + "\n");

            status = StatusLabel.Text = 
            "Entry Saved";

        writeButton.Enabled = false;

    }

   private void GetInfo (string fileName)
    {
        textBoxReadGrades.AppendText(File.ReadAllText(fileName));
    }

    private void ExitButton_Click(object sender, EventArgs e)
    {
        Application.Exit();
    }
}
}

Answer 1

您可以使用AppendText方法将文本附加到现有文件而不是覆盖：

using (StreamWriter sw = File.AppendText(sfd.FileName))
{
 ...
}

StreamWriter仅显示已保存文本文件中的最后一个输入，第一个输入在新行

1 个答案: