Question

我想打开一个文本文件，在其上添加一行，然后关闭它。

Answer 1

您可以使用File.AppendAllText：

File.AppendAllText(@"c:\path\file.txt", "text content" + Environment.NewLine);

Answer 2

using (StreamWriter w = File.AppendText("myFile.txt"))
{
  w.WriteLine("hello");
}

Answer 3

选择一个！但第一个很简单。最后一个可能是文件操作的工具：

//Method 1 (I like this)
File.AppendAllLines(
    "FileAppendAllLines.txt", 
    new string[] { "line1", "line2", "line3" });

//Method 2
File.AppendAllText(
    "FileAppendAllText.txt",
    "line1" + Environment.NewLine +
    "line2" + Environment.NewLine +
    "line3" + Environment.NewLine);

//Method 3
using (StreamWriter stream = File.AppendText("FileAppendText.txt"))
{
    stream.WriteLine("line1");
    stream.WriteLine("line2");
    stream.WriteLine("line3");
}

//Method 4
using (StreamWriter stream = new StreamWriter("StreamWriter.txt", true))
{
    stream.WriteLine("line1");
    stream.WriteLine("line2");
    stream.WriteLine("line3");
}

//Method 5
using (StreamWriter stream = new FileInfo("FileInfo.txt").AppendText())
{
    stream.WriteLine("line1");
    stream.WriteLine("line2");
    stream.WriteLine("line3");
}

Answer 4

可能想查看TextWriter课程。

//Open File
TextWriter tw = new StreamWriter("file.txt");

//Write to file
tw.WriteLine("test info");

//Close File
tw.Close();

Answer 5

或者您可以使用File.AppendAllLines(string, IEnumerable<string>)

File.AppendAllLines(@"C:\Path\file.txt", new[] { "my text content" });

Answer 6

File.AppendText将执行此操作：

using (StreamWriter w = File.AppendText("textFile.txt")) 
{
    w.WriteLine ("-------HURRAY----------");
    w.Flush();
}

Answer 7

技术上最好的方法可能就在这里：

private static async Task AppendLineToFileAsync([NotNull] string path, string line)
{
    if (string.IsNullOrWhiteSpace(path)) 
        throw new ArgumentOutOfRangeException(nameof(path), path, "Was null or whitepsace.");

    if (!File.Exists(path)) 
        throw new FileNotFoundException("File not found.", nameof(path));

    using (var file = File.Open(path, FileMode.Append, FileAccess.Write))
    using (var writer = new StreamWriter(file))
    {
        await writer.WriteLineAsync(line);
        await writer.FlushAsync();
    }
}

Answer 8

//我们可以使用

public StreamWriter（string path，bool append）;

打开文件时

StreamWriter SW = new StreamWriter（Path，true）;

第一个参数是用于保存文件完整路径的字符串第二个参数是Append Mode，在这种情况下是真的 string Path =＆＃34; C：\ MyFolder \ Notes.txt＆＃34;

可以使用

在文件上写入

SW.Write（字符串）

或

SW..WriteLine（字符串）

SW.WriteLine（＆＃34; Some Text＆＃34;）;

SW.Flush（）;

SW.Close（）;

示例代码

private void WriteAndAppend()
{
            string Path = Application.StartupPath + "\\notes.txt";
            FileInfo fi = new FileInfo(Path);
            StreamWriter SW;
            StreamReader SR;
            if (fi.Exists)
            {
                SR = new StreamReader(Path);
                string Line = "";
                while (!SR.EndOfStream) // Till the last line
                {
                    Line = SR.ReadLine();
                }
                SR.Close();
                int x = 0;
                if (Line.Trim().Length <= 0)
                {
                    x = 0;
                }
                else
                {
                    x = Convert.ToInt32(Line.Substring(0, Line.IndexOf('.')));
                }
                x++;
                SW = new StreamWriter(Path, true);
                SW.WriteLine("-----"+string.Format("{0:dd-MMM-yyyy hh:mm:ss tt}", DateTime.Now));
                SW.WriteLine(x.ToString() + "." + textBox1.Text);

            }
            else
            {
                SW = new StreamWriter(Path);
                SW.WriteLine("-----" + string.Format("{0:dd-MMM-yyyy hh:mm:ss tt}", DateTime.Now));
                SW.WriteLine("1." + textBox1.Text);
            }
            SW.Flush();
            SW.Close();
        }

Answer 9

//display sample reg form in notepad.txt
using (StreamWriter stream = new FileInfo("D:\\tt.txt").AppendText())//ur file location//.AppendText())
{
   stream.WriteLine("Name :" + textBox1.Text);//display textbox data in notepad
   stream.WriteLine("DOB : " + dateTimePicker1.Text);//display datepicker data in notepad
   stream.WriteLine("DEP:" + comboBox1.SelectedItem.ToString());
   stream.WriteLine("EXM :" + listBox1.SelectedItem.ToString());
}

打开现有文件，附加一行

9 个答案: