我尝试序列化和压缩一个WPF FlowDocument
,然后做相反的操作 - 解压缩字节数组并反序列化以重新创建FlowDocument - 使用 .NET 的GZipStream
类。我遵循MSDN上描述的示例,并有以下测试程序:
var flowDocumentIn = new FlowDocument();
flowDocumentIn.Blocks.Add(new Paragraph(new Run("Hello")));
Debug.WriteLine("Compress");
byte[] compressedData;
using (var uncompressed = new MemoryStream())
{
XamlWriter.Save(flowDocumentIn, uncompressed);
uncompressed.Position = 0;
using (var compressed = new MemoryStream())
using (var compressor = new GZipStream(compressed, CompressionMode.Compress))
{
Debug.WriteLine(" uncompressed.Length: " + uncompressed.Length);
uncompressed.CopyTo(compressor);
Debug.WriteLine(" compressed.Length: " + compressed.Length);
compressedData = compressed.ToArray();
}
}
Debug.WriteLine("Decompress");
FlowDocument flowDocumentOut;
using (var compressed = new MemoryStream(compressedData))
using (var uncompressed = new MemoryStream())
using (var decompressor = new GZipStream(compressed, CompressionMode.Decompress))
{
Debug.WriteLine(" compressed.Length: " + compressed.Length);
decompressor.CopyTo(uncompressed);
Debug.WriteLine(" uncompressed.Length: " + uncompressed.Length);
flowDocumentOut = (FlowDocument) XamlReader.Load(uncompressed);
}
Assert.AreEqual(flowDocumentIn, flowDocumentOut);
然而,在XamlReader.Load
行处我会收到异常,这很正常,因为调试输出显示未压缩的流长度为零。
Compress
uncompressed.Length: 123
compressed.Length: 202
Decompress
compressed.Length: 202
uncompressed.Length: 0
为什么最终的“未压缩”流不包含原始的123个字节?(请忽略“压缩”字节数组比“未压缩”字节数组大的事实——通常我会处理更大的流文档)