文件。AppendText会这样做:

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

您可以使用File。它的AppendAllText:

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

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

或者您可以使用File。AppendAllLines(字符串,IEnumerable <字符串>)

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

我们可以用

public StreamWriter(string path, bool append);

在打开文件时

string path="C:\\MyFolder\\Notes.txt"
StreamWriter writer = new StreamWriter(path, true);

第一个参数是保存完整文件路径的字符串 第二个参数是Append Mode，在本例中为true

写入文件可以通过:

writer.Write(字符串)

or

writer.WriteLine(字符串)

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();
        }

文件。AppendText会这样做:

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