附加到文本文件(不覆盖！)

本文关键字：覆盖 文件 文本 | 更新日期: 2023-09-27 18:28:30

我的另一个通用平台应用程序问题，还在学习中！

快速提问-我需要使用哪种将数据写入文本文件的方法将字符串附加（而不是覆盖）到文本文件？目前我正在使用一个使用流的异步void，但它正在覆盖我的文件。以下是创建和写入文本文件的不同方法：https://msdn.microsoft.com/en-us/library/windows/apps/mt185401.aspx

现在这是我的密码。是否需要修改以将数据附加到文本文件而不是覆盖它，或者我是否需要使用其他方法之一来附加数据？

//WRITE
        //Create the text file to hold the data
        Windows.Storage.StorageFolder storageFolder = Windows.Storage.ApplicationData.Current.LocalFolder;
        Windows.Storage.StorageFile ticketsFile = await storageFolder.CreateFileAsync("tickets.txt", Windows.Storage.CreationCollisionOption.OpenIfExists);
        //Use stream to write to the file
        var stream = await ticketsFile.OpenAsync(Windows.Storage.FileAccessMode.ReadWrite);
        using (var outputStream = stream.GetOutputStreamAt(0))
        {
            using (var dataWriter = new Windows.Storage.Streams.DataWriter(outputStream))
            {
                dataWriter.WriteString("Submitted: " + submitDate + "'n" + "Problem: " + problem + "'n" + "Room: " + location + "'n" + "Description: " + descriptionText.Text + "'n" + "Priority: " + priority + "'n");
                await dataWriter.StoreAsync();
                await outputStream.FlushAsync();
            }
        }
        stream.Dispose(); // Or use the stream variable (see previous code snippet) with a using statement as well.

如果它有任何不同，我的阅读代码：

//READ
        //Open the text file
        stream = await ticketsFile.OpenAsync(Windows.Storage.FileAccessMode.ReadWrite);
        ulong size = stream.Size;
        using (var inputStream = stream.GetInputStreamAt(0))
        {
            using (var dataReader = new Windows.Storage.Streams.DataReader(inputStream))
            {
                uint numBytesLoaded = await dataReader.LoadAsync((uint)size);
                string savedTickets = dataReader.ReadString(numBytesLoaded);
                textBox.Text = savedTickets;
            }
        }

谢谢。

附加到文本文件(不覆盖！)

我现在没有可以测试的平台，但这应该可以获得现有文件的长度，并将编写器放在末尾（新文件应该返回0）：

using (var outputStream = stream.GetOutputStreamAt(stream.Size))

除了获取流，您还可以使用FileIO类。例如方法AppendTextAsync:

await FileIO.AppendTextAsync(ticketsFile, "Submitted: " + submitDate + "'n" + "Problem: " + problem + "'n" + "Room: " + location + "'n" + "Description: " + descriptionText.Text + "'n" + "Priority: " + priority + "'n");
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