C# 即使使用 close() ，正在使用的文件，追加也不起作用

Question

我一直在尝试写这个以列出我的文件夹，附加部分不起作用，它会重写整个内容，如果我尝试在不退出应用程序的情况下列出其他内容，它会给出“文件正在使用”错误，这对我来说没有意义，因为我在每个循环结束时都使用了 close()。

我在这里检查了几乎所有 Microsoft 文档和大量帖子，但找不到我的答案。

The Picture that shows the Error I get

提前非常感谢！

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO;

namespace Anime_Lister
{
    public partial class Anime0Lister : Form
    {


        public void Appen()
        {
            using (System.IO.StreamWriter file = new System.IO.StreamWriter(path0save.Text, true))
            {


                DirectoryInfo directory = new DirectoryInfo(path0tb.Text);

                DirectoryInfo[] directory0Arr = directory.GetDirectories();

                foreach (DirectoryInfo dir in directory0Arr)
                {
                    String Parent = Convert.ToString(dir.Parent);
                    String Name = Convert.ToString(dir.Name);
                    String Root = Convert.ToString(dir.Root);


                    File.AppendAllText(path0save.Text, Parent);
                    File.AppendAllText(path0save.Text, "   || ");
                    File.AppendAllText(path0save.Text, Name + System.Environment.NewLine);
                    File.AppendAllText(path0save.Text, Root + System.Environment.NewLine);


                }

            }
        }

        public void Writer()
        {

            using (System.IO.StreamWriter file = new System.IO.StreamWriter(path0save.Text))
            {

                DirectoryInfo directory = new DirectoryInfo(path0tb.Text);

                DirectoryInfo[] directory0Arr = directory.GetDirectories();

                foreach (DirectoryInfo dir in directory0Arr)
                {
                    String Parent = Convert.ToString(dir.Parent);
                    String Name = Convert.ToString(dir.Name);
                    String Root = Convert.ToString(dir.Root);

                    file.Write(Parent);
                    file.Write("   || ");
                    file.WriteLine(Name);

                    file.WriteLine(Root);




                }

            }



        }


        public void Browser()
        {

            FolderBrowserDialog address = new FolderBrowserDialog();
            if (address.ShowDialog() == System.Windows.Forms.DialogResult.OK)
                path0tb.Text = address.SelectedPath;



        }

        public void Browser2()
        {

            if (saveFileDialog1.ShowDialog() == DialogResult.OK)
            {
                path0save.Text = saveFileDialog1.FileName;
            }



        }

        public Anime0Lister()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            //_____________________________________________________________List







            {

                try
                {


                    if (existing0file.Checked == true)
                    {
                        Appen();
                    }
                    else
                    {
                        Writer();
                    }    

                }


                catch (Exception Fail)
                {
                    MessageBox.Show(Fail.Message);


                }



            }

        }


    }
}

Answer 1

像StreamWriter 这样的一次性对象应始终包含在Using 语句中，以确保即使出现异常，该对象也会关闭并释放其非托管资源以供重用。该语言为此提供了一个特定的声明，（Using Stetement）但是，在您的特定情况下，如果您使用StreamWriter 打开文件，那么您不能使用File.AppendAllText，因为此方法会尝试自己打开文件并发现它被之前打开的 StreamWriter“使用”

    public void Appen()
    {
        using(System.IO.StreamWriter file = new System.IO.StreamWriter(path0save.Text, true))
        {
             DirectoryInfo directory = new DirectoryInfo(path0tb.Text);
             DirectoryInfo[] directory0Arr = directory.GetDirectories();

             foreach (DirectoryInfo dir in directory0Arr)
             {
                 // No need for those Convert.ToString. 
                 // The DirectoryInfo properties used are already strings.

                 file.Write(dir.Parent);
                 file.Write("   || ");
                 file.WriteLine(dir.Name);
                 file.WriteLine(dir.Root);

                 // or just in one line
                 //file.WriteLine(string.Concat(dir.Parent, 
                 //                      "   || ", 
                 //                      dir.Name, 
                 //                      Environment.NewLine,  
                 //                      dir.Root));  

            }
        }
    }

同样的 using 语句应该应用于 Writer 方法...