使用C#查找目錄中的專案是檔案還是檔案夾？

我想檢查目錄中的每個專案是否屬于檔案型別或使用 C# 的檔案夾。我想寫類似下面的代碼。但是IsInstanceOfType(FileInfo)andIsInstanceOfType(DirectoryInfo)在 C# 中是不允許的。

    DirectoryInfo dirPrograms = new DirectoryInfo(folderPath);                     
    foreach(var dir in dirPrograms.EnumerateFileSystemInfos())
        {
            if (dir.GetType().IsInstanceOfType(FileInfo))
                  //do something
            elseif (dir.GetType().IsInstanceOfType(DirectoryInfo))
                //do something
        }

uj5u.com熱心網友回復：

您可以使用is運算子來檢查物件是否可以轉換為特定型別：

if (dir is FileInfo)
  // do something
else (dir is DirectoryInfo)
  // Do something

uj5u.com熱心網友回復：

盡管您可以使用運算子解決此問題is，但我寧愿避免使用反射并通過檢查Attributes屬性來檢查它，如下所示：

foreach (var dir in dirPrograms.EnumerateFileSystemInfos())
{
    if (dir.Attributes.HasFlag(FileAttributes.Directory))
    {
        // It's a dir
    }
    else
    {
        // It's a file
    }
}

uj5u.com熱心網友回復：

您沒有讀取所有檔案夾的權限。因此，您需要遞回遍歷檔案夾并在遇到例外時繼續，如下面的代碼：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using System.Xml.Linq;
using System.IO;

namespace SAveDirectoriesXml
{
    class Program
    {
        const string FILENAME = @"c:\temp\test.xml";
        const string FOLDER = @"c:\temp";
        static XmlWriter writer = null;
        static void Main(string[] args)
        {
            XmlWriterSettings settings = new XmlWriterSettings();
            settings.Indent = true;

            writer = XmlWriter.Create(FILENAME, settings);
            writer.WriteStartDocument(true);

            DirectoryInfo info = new DirectoryInfo(FOLDER);
            WriteTree(info);
            
            writer.WriteEndDocument();
            writer.Flush();
            writer.Close();
            Console.WriteLine("Enter Return");
            Console.ReadLine();

        }
        static long WriteTree(DirectoryInfo info)
        {
            long size = 0;
            writer.WriteStartElement("Folder");
            try
            {
                writer.WriteAttributeString("name", info.Name);
                writer.WriteAttributeString("numberSubFolders", info.GetDirectories().Count().ToString());
                writer.WriteAttributeString("numberFiles", info.GetFiles().Count().ToString());
                writer.WriteAttributeString("date", info.LastWriteTime.ToString());
             

                foreach (DirectoryInfo childInfo in info.GetDirectories())
                {
                    size  = WriteTree(childInfo);
                }
                
            }
            catch (Exception ex)
            {
                string errorMsg = string.Format("Exception Folder : {0}, Error : {1}", info.FullName, ex.Message);
                Console.WriteLine(errorMsg);
                writer.WriteElementString("Error", errorMsg);
            }

            FileInfo[] fileInfo = null;
            try
            {
                fileInfo = info.GetFiles();
            }
            catch (Exception ex)
            {
                string errorMsg = string.Format("Exception FileInfo : {0}, Error : {1}", info.FullName, ex.Message);
                Console.WriteLine(errorMsg);
                writer.WriteElementString("Error",errorMsg);
            }

            if (fileInfo != null)
            {
                foreach (FileInfo finfo in fileInfo)
                {
                    try
                    {
                        writer.WriteStartElement("File");
                        writer.WriteAttributeString("name", finfo.Name);
                        writer.WriteAttributeString("size", finfo.Length.ToString());
                        writer.WriteAttributeString("date", info.LastWriteTime.ToString());
                        writer.WriteEndElement();
                        size  = finfo.Length;
                    }
                    catch (Exception ex)
                    {
                        string errorMsg = string.Format("Exception File : {0}, Error : {1}", finfo.FullName, ex.Message);
                        Console.WriteLine(errorMsg);
                        writer.WriteElementString("Error", errorMsg);
                    }
                }
            }

            writer.WriteElementString("size", size.ToString());
            writer.WriteEndElement();
            return size;

        }
    }
}

uj5u.com熱心網友回復：

您還可以使用FileSystemInfo.FullPathand 然后使用DirectoryandFile類來檢查檔案或檔案夾是否存在。

所以在你的foreach回圈中它會是這樣的。

if (Directory.Exists(dir.FullPath))
     // do something it its a folder
elseif (File.Exists(dir.FullPath))
     // do something if its a file, shouldn't have to check this condition really but it wouldn't hurt to be safe

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