c# - 提高 TextFile 的读取效率(更大的文件类型)

Question

以下是我的代码，但一次不能处理超过 500 行。

需要在行尾加一个,，同时进行检测。我目前正在做的是将它们分成 2 个不同的文本框，然后通过复制粘贴保存我需要的文本框，但如果文件太大，应用程序似乎会挂起。

有人可以帮助我提高效率吗？非常感谢。

 private void button1_Click_1(object sender, EventArgs e)
    {
        if (openFileDialog1.ShowDialog() == DialogResult.Cancel)
            return;

        System.IO.StreamReader Reader = new System.IO.StreamReader(openFileDialog1.FileName);

        //Create a filestream

        FileStream fStr;

        try
        {
            //Set filestream to the result of the pick of the user

            fStr = new FileStream(openFileDialog1.FileName, FileMode.Open, FileAccess.Read);


            //Create a streamreader, sr, to read the file

            StreamReader sr = new StreamReader(fStr);

            //While the end of the file has not been reached...

            while (sr.Peek() >= 0)
            {
                //Create a 'line' that contains the current line of the textfile

                string line = sr.ReadLine().ToLower();

                if (line.Contains("staff"))
                {

                    line += ","; //Add a , to the end of the line**Important**
                    textBox1.Text += line + Environment.NewLine;
                    releventcount += 1;
                }
                else
                {
                    line += ","; //Add a , to the end of the line**Important**
                    textBox2.Text += line + Environment.NewLine;
                    irreleventcount += 1;
                }

                label1.Text = "Relevent: ";
                label2.Text = "Irrelevant: ";
            }
            //Close the file so other modules can access it
            sr.Close();
            //If something goes wrong, tell the user
        }
        catch (Exception)
        {

            MessageBox.Show("Error opening file", "Check the CODE ! ~.~");
        }


    }

Answer 1

我不确定您最终要在这里完成什么。有几种更简洁的方法可以完成您当前代码正在做的事情，但它们不会显着提高阅读速度。

您代码中的瓶颈在于您要追加字符串。使用 StringBuilder这是个好建议，但您可以通过创建一个 List<string> 来做得更好然后调用string.Join在最后。例如:

if (openFileDialog1.ShowDialog() == DialogResult.Cancel)
    return;
List<string> staff = new List<string>();
List<string> other = new List<string>();

foreach (var line in File.ReadLines(openFileDialog1.FileName))
{
    line = line.ToLower();
    if (line.Contains("staff"))
    {
        staff.Add(line);
    }
    else
    {
        other.Add(line);
    }
}

relevantcount = staff.Count;
irrelevantCount = other.Count;

textBox1.Text = string.Join(","+Environment.NewLine, staff);
textBox2.Text = string.Join("."+Environment.NewLine, other);

此外，您说您的代码一次只能处理 500 行。您的用户界面中是否有某些东西阻止它处理更多？当然，您显示的代码中没有任何内容具有如此低的限制。