获取指定文件夹内的文件

首先需要定义文件信息记录类：

    public class FileData
    {
        private string myFullName;
        private string myName;
        private string myExtension;
        private long myLength;

        public  FileData(){}

        public  FileData( string strFullName, string strName, string strExtension, long intLength )
        {
            this.myFullName = strFullName;
            this.myName = strName;
            this.myExtension = strExtension;
            this.myLength = intLength;
        }

        public string FullName
        {
            get
            {
                return this.myFullName;
            }
        }

        public string Name
        {
            get
            {
                return this.myName;
            }
        }

        public string Extension
        {
            get
            {
                return this.myExtension;
            }
        }

        public long Length
        {
            get
            {
                return this.myLength;
            }
        }

        public override string ToString()
        {
            return this.myFullName;
        }
    }

定义查找文件类（可递归）：

    public class FileExplorer
    {
        public ArrayList FileList = new ArrayList();
        public ArrayList Extensions = null;
        private string Path = "";
        private bool Recursive = true;

        public FileExplorer( string path  )
        {
            this.Path = path;
            this.Recursive = false;
            this.FileList = this.getFiles();
        }

        public FileExplorer( string path, ArrayList extensions  )
        {
            this.Path = path;
            this.Extensions = extensions;
            this.Recursive = false;
            this.FileList = this.getFiles();
        }

        public FileExplorer( string path, bool recursive  )
        {
            this.Path = path;
            this.Recursive = recursive;
            this.FileList = this.getFiles();
        }

        public FileExplorer( string path, ArrayList extensions, bool recursive  )
        {
            this.Path = path;
            this.Extensions = extensions;
            this.Recursive = recursive;
            this.FileList = this.getFiles();
        }

        public ArrayList getFiles()
        {
            DirectoryInfo   dir = new DirectoryInfo( this.Path );
            FileInfo[]      files;
            DirectoryInfo[] dirs;
            ArrayList List = new ArrayList();
                   if (! dir.Exists)
            {
                throw new Exception("文件夹不存在: " + this.Path );
            }

            files = dir.GetFiles();

            foreach(FileInfo file in files)
            {
                if( this.Extensions == null )
                {
                    List.Add( new FileData( file.FullName, file.Name, file.Extension, file.Length ) );
                }
                else 
                {
                    if( this.checkFile( file.Extension ) )
                    {
                        List.Add( new FileData( file.FullName, file.Name, file.Extension, file.Length ) );
                    }
                }
            }

            files = null;
        
            if (! this.Recursive)
            {
                return List;
            }

            dirs = dir.GetDirectories();

            foreach(DirectoryInfo subdir in dirs)
            {
                this.Path = subdir.FullName;
                ArrayList temp = new ArrayList();
                temp = getFiles();
                for(int i=0; i < temp.Count; i++)
                {
                    FileData TempData = (FileData)temp[i];
                    List.Add( new FileData( TempData.FullName, TempData.Name, TempData.Extension, TempData.Length ) );
                }
            }
        
            dirs = null;
        
            dir = null;

            return List;
        }

        private bool checkFile( string strExtension )
        {
            bool throwaway = true;
            for(int j=0; j<this.Extensions.Count; j++)
            {
                if( this.Extensions[j].ToString() == strExtension )
                {
                    throwaway = false;
                }
            }

            if( throwaway )
            {
                return false;
            }
            else
            {
                return true;
            }
        }

    }