从文本文件中读取C＃ [英] Reading From a Text File in C#

问题描述

我有以下程序将发送（输出）信息到文本文件，但现在我想从文本文件中读取（输入）。任何建议将非常感谢。我已经注释了一些我认为我需要做的事情;但我不确定如何继续。

 使用System.Windows.Forms; 
 using System.IO; 
 
命名空间Input_Output 
 {
 public partial class成绩：表单
 {
私人StreamWriter输出; 
 
 private StreamReader输入; 
 
 
 public Grades（）
 {
 InitializeComponent（）; 
} 
 
 private void label4_Click（object sender，EventArgs e）
 {
 
} 
 
 private void btnCreate_Click sender，EventArgs e）
 {
 btnEnter.Visible = true; 
 btnClose.Visible = true; 
 txtFirst.Visible = true; 
 txtLast.Visible = true; 
 lblFirst.Visible = true; 
 lblLast.Visible = true; 
 listBox1.Visible = true; 
 lblStatus.Visible = true; 
 lblGrade.Visible = true; 
 lblCourse.Visible = true; 
 cmbID.Visible = true; 
 lblID.Visible = true; 
 txtCourse.Visible = true; 
 txtGrade.Visible = true; 
 lblStatus.Visible = true; 
 
 DialogResult result; 
 string fileName; 
 using（SaveFileDialog chooser = new SaveFileDialog（））
 {
 result = chooser.ShowDialog（）; 
 fileName = Chooser.FileName; 
} 
 output = new StreamWriter（fileName）; 
 btnCreate.Enabled = false; 
 txtFirst.Visible = true; 
 txtLast.Visible = true; 
 lblFirst.Visible = true; 
 lblLast.Visible = true; 
 btnEnter.Visible = true; 
 btnClose.Visible = true; 
} 
 
 
 private void btnClose_Click（object sender，EventArgs e）
 {
 //关闭按钮将列表框中的信息推送到文本文件
 
 output.Close（）; 
 lblStatus.ForeColor = Color.Red; 
 lblStatus.Text =输出文件; 
 btnCreate.Enabled = true; 
 listBox1.Items.Clear（）; 
 cmbID.Text =; 
} 
 
 private void btnEnter_Click（object sender，EventArgs e）
 {
 //输入按钮发送信息到列表框，消息框提示用户检查为准确。 
 //关闭按钮将信息推送到文本文件。 
 string last =; 
 string first =; 
 string course=; 
 string grade =; 
 
 if（txtFirst.Text！=& txtLast.Text！=&& txtCourse.Text！=）
 {
 last = txtFirst.Text; 
 first = txtLast.Text; 
 course = txtCourse.Text; 
 grade = txtGrade.Text; 
 output.WriteLine（last +\t+\t+ first +：+\t+ cmbID.SelectedItem +_+ course +_+ grade） ; 
 
 listBox1.Items.Add（txtLast.Text +，+ txtFirst.Text +：+ cmbID.SelectedItem + - + txtCourse.Text + - + txtGrade.Text） ; 
 lblStatus.ForeColor = Color.Navy; 
 lblStatus.Text =Entry Saved; 
 txtFirst.Text =; 
 txtLast.Text =; 
 txtCourse.Text =; 
 txtGrade.Text =; 
 txtFirst.Focus（）; 
} 
 else 
 {
 lblStatus.ForeColor = Color.Red; 
 lblStatus.Text =空文本框或框; 
} 
 MessageBox.Show（请在继续之前验证信息是否正确）; 
} 
 
 private void btnExit_Click（object sender，EventArgs e）
 {
 Application.Exit（）; 
} 
 
 private void Grades_Load（object sender，EventArgs e）
 {
 
} 
 
 private void button1_Click sender，EventArgs e）
 {
 DialogResult result; 
 string fileName; 
 using（OpenFileDialog chooser = new OpenFileDialog（））
 {
 result = chooser.ShowDialog（）; 
 fileName = chooser.FileName; 
} 
 // while循环？ 
 //如果变量为null，它是记录的结尾
 // variable =！null 
 // txt读取int变量TxtFile.Text + = Rec +\r\ n。 while rec！= null; 
} 
} 
} 
  

解决方案>

要一次读取一行文本文件，您可以这样做：

 使用System.IO; 
 
使用（var reader = new StreamReader（fileName））
 {
 string line; 
 while（（line = reader.ReadLine（））！= null）
 {
 //在这里做你的行，它将为每个
 //行调用文件中的文本。 
} 
} 
  

还有其他方法。例如，如果文件不是太大，并且您只想将所有内容读取到单个字符串，则可以使用 File.ReadAllText（）

  myTextBox.Text = File.ReadAllText（fileName）; 
  

I have the following program that will send (output) information to a text file, but now I want to read (input) from the text file. Any suggestions would be greatly appreciated. I have commented out a couple of things that "I think" I need to do; but I am not really certain how to proceed.

using System.Windows.Forms;
using System.IO;

namespace Input_Output
{
    public partial class Grades : Form
    {
        private StreamWriter output;

        private StreamReader input;


        public Grades()
        {
            InitializeComponent();
        }

        private void label4_Click(object sender, EventArgs e)
        {

        }

        private void btnCreate_Click(object sender, EventArgs e)
        {
            btnEnter.Visible = true;
            btnClose.Visible = true;
            txtFirst.Visible = true;
            txtLast.Visible = true;
            lblFirst.Visible = true;
            lblLast.Visible = true;
            listBox1.Visible = true;
            lblStatus.Visible = true;
            lblGrade.Visible = true;
            lblCourse.Visible = true;
            cmbID.Visible = true;
            lblID.Visible = true;
            txtCourse.Visible = true;
            txtGrade.Visible = true;
            lblStatus.Visible = true;

            DialogResult result;
            string fileName;
            using (SaveFileDialog chooser = new SaveFileDialog())
            {
                result = chooser.ShowDialog();
                fileName = chooser.FileName;
            }
            output = new StreamWriter(fileName);
            btnCreate.Enabled = false;
            txtFirst.Visible = true;
            txtLast.Visible = true;
            lblFirst.Visible = true;
            lblLast.Visible = true;
            btnEnter.Visible = true;
            btnClose.Visible = true;
        }


        private void btnClose_Click(object sender, EventArgs e)
        {
            //Close button pushes information from the listbox in to the text file

            output.Close();
            lblStatus.ForeColor = Color.Red;
            lblStatus.Text = "Output File";
            btnCreate.Enabled = true;
            listBox1.Items.Clear();
            cmbID.Text = "";
        }

        private void btnEnter_Click(object sender, EventArgs e)
        {
            // Enter button sends information to the list box, a Message Box prompts user to check for accuracy.  
            //Close button pushes information to the Text file.
            string last = "";
            string first = "";
            string course = "";
            string grade = "";

            if (txtFirst.Text != "" && txtLast.Text != "" && txtCourse.Text != "")
            {
                last = txtFirst.Text;
                first = txtLast.Text;
                course = txtCourse.Text;
                grade = txtGrade.Text;
                output.WriteLine (last + "\t"+ "\t" + first + ":"+ "\t" + cmbID.SelectedItem + "_" + course + "_" + grade );

                listBox1.Items.Add(txtLast.Text + "," + txtFirst.Text + ":" + cmbID.SelectedItem + "-" + txtCourse.Text + "-" + txtGrade.Text);
                lblStatus.ForeColor = Color.Navy;
                lblStatus.Text = "Entry Saved";
                txtFirst.Text = "";
                txtLast.Text = "";
                txtCourse.Text = "";
                txtGrade.Text = "";
                txtFirst.Focus();
            }
            else
            {     
                lblStatus.ForeColor = Color.Red;
                lblStatus.Text = "Empty text box or boxes";
            }
            MessageBox.Show("Please verify that the information is correct before proceeding");
        }

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

        private void Grades_Load(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)
        {
            DialogResult result;
            string fileName;
            using (OpenFileDialog chooser = new OpenFileDialog())
            {
                result = chooser.ShowDialog();
                fileName = chooser.FileName;
            }
            //while loop?
            //if variable is null, it's the end of the record
            //variable= !null 
            //txt read int variable TxtFile.Text += Rec + "\r\n";   while rec !=null;
        }
    }
}

解决方案

To read a text file one line at a time you can do like this:

using System.IO;

using (var reader = new StreamReader(fileName))
{
    string line;
    while ((line = reader.ReadLine()) != null)
    {
        // Do stuff with your line here, it will be called for each 
        // line of text in your file.
    }
}

There are other ways as well. For example, if the file isn't too big and you just want everything read to a single string, you can use File.ReadAllText()

myTextBox.Text = File.ReadAllText(fileName);

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