StreamReader srAsciiFromFile =  new StreamReader("C:\\Temp\\Test.txt", System.Text.Encoding.ASCII);
StreamReader srAsciiFromStream = new StreamReader( (System.IO.Stream)File.OpenRead("C:\\Temp\\Test.txt"),System.Text.Encoding.ASCII);

using (StreamReader sr = new StreamReader(path))
{
    while (sr.Peek() >= 0)
    {
        Console.Write((char)sr.Read());
    }
}

static async Task Main()
{
    await ReadAndDisplayFilesAsync();
}

static async Task ReadAndDisplayFilesAsync()
{
    String filename = "C:\\s.xml";
    Char[] buffer;

    using (var sr = new StreamReader(filename))
    {
        buffer = new Char[(int)sr.BaseStream.Length];
       await sr.ReadAsync(buffer, 0, (int)sr.BaseStream.Length);
    }

    Console.WriteLine(new String(buffer));
}

using (StreamReader sr = new StreamReader("TestFile.txt"))
{
    string line;
    // Read and display lines from the file until the end of the file is reached.
    while ((line = sr.ReadLine()) != null)
    {
        Console.WriteLine(line);
    }
}

using (StreamReader sr = new StreamReader(path))
{
    Console.WriteLine(sr.ReadToEnd());
}

//保留文件現(xiàn)有數(shù)據(jù)，以追加寫入的方式打開d:\file.txt文件
using (StreamWriter sw = new StreamWriter(@"d:\file.txt", true)) //true 表示追加
{
    //向文件寫入新字符串，并關閉StreamWriter
    sw.WriteLine("Another File Operation Method");
}