samples/snippets/csharp/events/Program.cs - main - aprogrammer/dotnet-docs

samples/snippets/csharp/events/Program.cs
159 строк5 KB
Genevieve Warren
Fix nullability warnings (remaining /samples/snippets/csharp projects) (#35176)
27 апр 2023, 20:58
27 апр 2023, 20:58ca8ed8a
 using System.IO;

namespace EventSampleCode
{
    class Program
    {
        static void Main(string[] args)
        {
            // <SnippetDeclareEventHandler>
            var fileLister = new FileSearcher();
            int filesFound = 0;

            EventHandler<FileFoundArgs> onFileFound = (sender, eventArgs) =>
            {
                Console.WriteLine(eventArgs.FoundFile);
                filesFound++;
            };

            fileLister.FileFound += onFileFound;
            // </SnippetDeclareEventHandler>

            // <SnippetSearch>
            fileLister.DirectoryChanged += (sender, eventArgs) =>
            {
                Console.Write($"Entering '{eventArgs.CurrentSearchDirectory}'.");
                Console.WriteLine($" {eventArgs.CompletedDirs} of {eventArgs.TotalDirs} completed...");
            };
            // </SnippetSearch>

            fileLister.Search(".", "*.dll", true);

            // <SnippetRemoveHandler>
            fileLister.FileFound -= onFileFound;
            // </SnippetRemoveHandler>
        }
    }

    // <SnippetEventArgs>
    public class FileFoundArgs : EventArgs
    {
        public string FoundFile { get; }
        public bool CancelRequested { get; set; }

        public FileFoundArgs(string fileName) => FoundFile = fileName;
    }
    // </SnippetEventArgs>

    // <SnippetSearchDirEventArgs>
    internal class SearchDirectoryArgs : EventArgs
    {
        internal string CurrentSearchDirectory { get; }
        internal int TotalDirs { get; }
        internal int CompletedDirs { get; }

        internal SearchDirectoryArgs(string dir, int totalDirs, int completedDirs)
        {
            CurrentSearchDirectory = dir;
            TotalDirs = totalDirs;
            CompletedDirs = completedDirs;
        }
    }
    // </SnippetSearchDirEventArgs>

    public class FileSearcher
    {
        // <SnippetDeclareEvent>
        public event EventHandler<FileFoundArgs>? FileFound;
        // </SnippetDeclareEvent>
        // <SnippetDeclareSearchEvent>
        internal event EventHandler<SearchDirectoryArgs> DirectoryChanged
        {
            add { _directoryChanged += value; }
            remove { _directoryChanged -= value; }
        }
        private EventHandler<SearchDirectoryArgs>? _directoryChanged;
        // </SnippetDeclareSearchEvent>

        // <SnippetFinalImplementation>
        public void Search(string directory, string searchPattern, bool searchSubDirs = false)
        {
            if (searchSubDirs)
            {
                var allDirectories = Directory.GetDirectories(directory, "*.*", SearchOption.AllDirectories);
                var completedDirs = 0;
                var totalDirs = allDirectories.Length + 1;
                foreach (var dir in allDirectories)
                {
                    RaiseSearchDirectoryChanged(dir, totalDirs, completedDirs++);
                    // Search 'dir' and its subdirectories for files that match the search pattern:
                    SearchDirectory(dir, searchPattern);
                }
                // Include the Current Directory:
                RaiseSearchDirectoryChanged(directory, totalDirs, completedDirs++);
                
                SearchDirectory(directory, searchPattern);
            }
            else
            {
                SearchDirectory(directory, searchPattern);
            }
        }
        
        private void SearchDirectory(string directory, string searchPattern)
        {
            foreach (var file in Directory.EnumerateFiles(directory, searchPattern))
            {
                FileFoundArgs args = RaiseFileFound(file);
                if (args.CancelRequested)
                {
                    break;
                }
            }
        }

        private void RaiseSearchDirectoryChanged(
            string directory, int totalDirs, int completedDirs) =>
            _directoryChanged?.Invoke(
                this,
                    new SearchDirectoryArgs(directory, totalDirs, completedDirs));

        private FileFoundArgs RaiseFileFound(string file)
        {
            var args = new FileFoundArgs(file);
            FileFound?.Invoke(this, args);
            return args;
        }
        // </SnippetFinalImplementation>
    }
}

namespace VersionOne
{
    // <SnippetEventArgsV1>
    public class FileFoundArgs : EventArgs
    {
        public string FoundFile { get; }

        public FileFoundArgs(string fileName) => FoundFile = fileName;
    }
    // </SnippetEventArgsV1>

    // <SnippetFileSearcherV1>
    public class FileSearcher
    {
        public event EventHandler<FileFoundArgs>? FileFound;

        public void Search(string directory, string searchPattern)
        {
            foreach (var file in Directory.EnumerateFiles(directory, searchPattern))
            {
                RaiseFileFound(file);
            }
        }
        
        private void RaiseFileFound(string file) =>
            FileFound?.Invoke(this, new FileFoundArgs(file));
    }
    // </SnippetFileSearcherV1>
}