在C#中读/写文本文件进度条

Question

我有一个函数,它读取一个大文本文件,拆分一个部分(从给定的开始和结束),并将拆分的数据保存到另一个文本文件.因为文件太大,我需要在读取流时添加进度条将分割文本写入另一个文件时另一个.Ps.start和end给出datetime !!

using (StreamReader sr = new StreamReader(file,System.Text.Encoding.ASCII))
{
    while (sr.EndOfStream == false)
    {
        line = sr.ReadLine();

        if (line.IndexOf(start) != -1)
        {
            using (StreamWriter sw = new StreamWriter(DateTime.Now.ToString().Replace("/", "-").Replace(":", "-") + "cut"))
            {
                sw.WriteLine(line);
                while (sr.EndOfStream == false && line.IndexOf(end) == -1)
                {
                    line = sr.ReadLine();
                    sw.WriteLine(line);
                }
            }

            richTextBox1.Text += "done ..." + "\n";
            break;
        }
    }
}

Answer 1

首先要做的是计算文件使用FileInfo的时间,

http://msdn.microsoft.com/en-us/library/system.io.fileinfo.aspx

FileInfo fileInfo = new FileInfo(file);
long length = fileInfo.Length;

我建议你这样做,

private long currentPosition = 0;

private void UpdateProgressBar(int lineLength)
{
    currentPosition += line.Count; // or plus 2 if you need to take into account carriage return
    progressBar.Value = (int)(((decimal)currentPosition / (decimal)length) * (decimal)100);
}

private void CopyFile()
{
    progressBar.Minimum = 0;
    progressBar.Maximum = 100;

    currentPosition = 0;

    using (StreamReader sr = new StreamReader(file,System.Text.Encoding.ASCII))
    {
        while (sr.EndOfStream == false)
        {
            line = sr.ReadLine();
            UpdateProgressBar(line.Length);

            if (line.IndexOf(start) != -1)
            {
                using (StreamWriter sw = new StreamWriter(DateTime.Now.ToString().Replace("/", "-").Replace(":", "-") + "cut"))
                {
                    sw.WriteLine(line);
                    while (sr.EndOfStream == false && line.IndexOf(end) == -1)
                    {
                        line = sr.ReadLine();
                        UpdateProgressBar(line.Length);
                        sw.WriteLine(line);
                    }
                }

                richTextBox1.Text += "done ..." + "\n";
                break;
            }
        }
    }
}

这是计算已读取文件的百分比并将进度条设置为该值.然后你不必担心长度是否很长,进度条使用int.

如果您不想截断该值,则执行此操作(转换为上面的int将始终截断小数,从而向下舍入),

progressBar.Value = (int)Math.Round(((decimal)currentPosition / (decimal)length) * (decimal)100), 0);

这是在后台线程吗？不要忘记你必须调用this.Invoke更新进度条,否则你将得到一个跨线程异常.