我知道 WinRT 中的 IRandomAccessStream 接口有两个类，FileRandomAccessStream 和 InMemoryRandomAccessStream。
现在我将我的一个应用程序移植到 wp8，我的一些方法需要 IRandomAccessStream 作为返回类型，但我找不到 InMemoryRandomAccessStream。
在 Windows Phone 8 中没有 InMemoryRandomAccessStream 的情况下，如何创建内存流并从中获取 IRandomAccessStream？
遇到同样的事情。我最终使用了一个随机访问的临时文件流。
这是从
windows.storage.applicationdata.temporaryfolder实际上没有实现，所以我在本地文件夹中创建了一个文件（确保在之后删除它，因为你想要一些临时的东西？）。
和
windows.storage.streams.inmemoryrandomaccessstream
这是稍微采用的示例代码：
private async void TransferData()//object sender, RoutedEventArgs e)
{
Windows.Storage.StorageFolder temporaryFolder = ApplicationData.Current.LocalFolder;
// Write data to a file
StorageFile sampleFile = await temporaryFolder.CreateFileAsync("tempStream.txt", Windows.Storage.CreationCollisionOption.ReplaceExisting);
IRandomAccessStream acccessStream = await sampleFile.OpenAsync(FileAccessMode.ReadWrite);
// Initialize the in-memory stream where data will be stored.
using (var stream = acccessStream)
{
// Create the data writer object backed by the in-memory stream.
using (var dataWriter = new Windows.Storage.Streams.DataWriter(stream))
{
dataWriter.UnicodeEncoding = Windows.Storage.Streams.UnicodeEncoding.Utf8;
dataWriter.ByteOrder = Windows.Storage.Streams.ByteOrder.LittleEndian;
// Parse the input stream and write each element separately.
string[] inputElements = "this;really;works".Split(';');
foreach (string inputElement in inputElements)
{
uint inputElementSize = dataWriter.MeasureString(inputElement);
dataWriter.WriteUInt32(inputElementSize);
dataWriter.WriteString(inputElement);
System.Diagnostics.Debug.WriteLine("Wrote: " + inputElement);
}
// Send the contents of the writer to the backing stream.
await dataWriter.StoreAsync();
// For the in-memory stream implementation we are using, the flushAsync call
// is superfluous,but other types of streams may require it.
await dataWriter.FlushAsync();
// In order to prolong the lifetime of the stream, detach it from the
// DataWriter so that it will not be closed when Dispose() is called on
// dataWriter. Were we to fail to detach the stream, the call to
// dataWriter.Dispose() would close the underlying stream, preventing
// its subsequent use by the DataReader below.
dataWriter.DetachStream();
}
// Create the input stream at position 0 so that the stream can be read
// from the beginning.
using (var inputStream = stream.GetInputStreamAt(0))
{
using (var dataReader = new Windows.Storage.Streams.DataReader(inputStream))
{
// The encoding and byte order need to match the settings of the writer
// we previously used.
dataReader.UnicodeEncoding = Windows.Storage.Streams.UnicodeEncoding.Utf8;
dataReader.ByteOrder = Windows.Storage.Streams.ByteOrder.LittleEndian;
// Once we have written the contents successfully we load the stream.
await dataReader.LoadAsync((uint)stream.Size);
var receivedStrings = "";
// Keep reading until we consume the complete stream.
while (dataReader.UnconsumedBufferLength > 0)
{
// Note that the call to readString requires a length of "code units"
// to read. This is the reason each string is preceded by its length
// when "on the wire".
uint bytesToRead = dataReader.ReadUInt32();
receivedStrings += dataReader.ReadString(bytesToRead) + "\n";
}
// Populate the ElementsRead text block with the items we read
// from the stream.
System.Diagnostics.Debug.WriteLine("Read: " + receivedStrings);
}
}
}
}
确保使用 windows.storage 命名空间。
关键是这一行：
IRandomAccessStream 访问流 = 等待 sampleFile.OpenAsync(FileAccessMode.ReadWrite);
我不确定速度的影响是什么。