无法在 UWP (Windows 10 App) C# 中压缩空白文本文件（大小 0KB）

Question

我有一个 UWP 应用程序（通用 Windows 平台）。我正在尝试压缩文件夹及其内容（子文件夹、图像、文本文件）。

如果文本文件不为空，则效果很好。

但是当任何文本文件为空白或空（0KB 大小）时它会给出异常。

错误如下：

{System.ArgumentException: The specified buffer index is not within the buffer capacity. at System.Runtime.InteropServices.WindowsRuntime.WindowsRuntimeBufferExtensions.ToArray(IBuffer source, UInt32 sourceIndex, Int32 count) at System.Runtime.InteropServices.WindowsRuntime.WindowsRuntimeBufferExtensions.ToArray(IBuffer source) at SmartflowRuntimes.Service.d__54.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at SmartflowRuntimes.Service.d__54.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at SmartflowRuntimes.Service.d__53.MoveNext()}

这是我的代码：

public async Task<string> ZipHelper(string zipFileName)
{
    try
    {
        string appFolderPath = ApplicationData.Current.LocalFolder.Path;
        StorageFolder destnFolder = await StorageFolder.GetFolderFromPathAsync(appFolderPath + "\destn");
        StorageFolder sourceFolder = await StorageFolder.GetFolderFromPathAsync(appFolderPath + "\src");

        StorageFile zipFile = await destnFolder.CreateFileAsync(zipFileName, CreationCollisionOption.ReplaceExisting);
        Stream zipToCreate = await zipFile.OpenStreamForWriteAsync();
        ZipArchive archive = new ZipArchive(zipToCreate, ZipArchiveMode.Update);

        await ZipFolderContents(sourceFolder, archive, sourceFolder.Path);
        archive.Dispose();
        return "success";
    }
    catch (Exception ex)
    {
        return "fail";
    }
}

public async Task ZipFolderContents(StorageFolder sourceFolder, ZipArchive archive, string baseDirPath)
{
    IReadOnlyList<StorageFile> files = await sourceFolder.GetFilesAsync();

    foreach (StorageFile file in files)
    {
        ZipArchiveEntry readmeEntry = archive.CreateEntry(file.Path.Remove(0, baseDirPath.Length));
        byte[] buffer = WindowsRuntimeBufferExtensions.ToArray(await FileIO.ReadBufferAsync(file));
        using (Stream entryStream = readmeEntry.Open())
        {
            await entryStream.WriteAsync(buffer, 0, buffer.Length);
        }
    }

    IReadOnlyList<StorageFolder> subFolders = await sourceFolder.GetFoldersAsync();

    if (subFolders.Count() == 0) return;

    foreach (StorageFolder subfolder in subFolders)
        await ZipFolderContents(subfolder, archive, baseDirPath);
}

这个问题有解决办法吗？谢谢

Answer 1

此 System.ArgumentException 是从 WindowsRuntimeBufferExtensions.ToArray 方法中抛出的，该方法期望 IBuffer 的大小大于 0。

因此，要解决此问题，请在调用此方法之前检查文件大小，就像您可能经常在调用其方法之前检查对象引用是否为 null 一样。

ZipArchiveEntry readmeEntry = archive.CreateEntry(file.Path.Remove(0, baseDirPath.Length));

ulong fileSize = (await file.GetBasicPropertiesAsync()).Size;                
byte[] buffer = fileSize > 0 ? (await FileIO.ReadBufferAsync(file)).ToArray() 
                : new byte[0];

using (Stream entryStream = readmeEntry.Open())
{
    await entryStream.WriteAsync(buffer, 0, buffer.Length);                    
}

顺便说一句，WindowsRuntimeBufferExtensions.ToArray 是一个 extension method，它使您能够在 IBuffer 实例上调用不存在的 ToArray 方法（因此称为扩展方法） .我也展示了如何以更方便的方式调用它。

无法在 UWP (Windows 10 App) C# 中压缩空白文本文件（大小 0KB）

Couldn't zip blank text file (size 0KB) in UWP (Windows 10 App) C#

c#

windows-runtime

uwp

windows-10-universal