如何读取数据从一个压缩文件，而不必解压缩整个文件

Something like this will list and extract the files one by one, if you want to use SharpZipLib:

var zip = new ZipInputStream(File.OpenRead(@"C:\Users\Javi\Desktop\myzip.zip"));
var filestream = new FileStream(@"C:\Users\Javi\Desktop\myzip.zip", FileMode.Open, FileAccess.Read);
ZipFile zipfile = new ZipFile(filestream);
ZipEntry item;
while ((item = zip.GetNextEntry()) != null)
{
Console.WriteLine(item.Name);
using (StreamReader s = new StreamReader(zipfile.GetInputStream(item)))
{
// stream with the file
Console.WriteLine(s.ReadToEnd());
}
}

Based on this example: content inside zip file

Zip files have a table of contents. Every zip utility should have the ability to query just the TOC. Or you can use a command line program like 7zip -t to print the table of contents and redirect it to a text file.

DotNetZip is your friend here.

As easy as:

using (ZipFile zip = ZipFile.Read(ExistingZipFile))
{
ZipEntry e = zip["MyReport.doc"];
e.Extract(OutputStream);
}

(you can also extract to a file or other destinations).

Reading the zip file's table of contents is as easy as:

using (ZipFile zip = ZipFile.Read(ExistingZipFile))
{
foreach (ZipEntry e in zip)
{
if (header)
{
System.Console.WriteLine("Zipfile: {0}", zip.Name);
if ((zip.Comment != null) && (zip.Comment != ""))
System.Console.WriteLine("Comment: {0}", zip.Comment);
System.Console.WriteLine("\n{1,-22} {2,8}  {3,5}   {4,8}  {5,3} {0}",
"Filename", "Modified", "Size", "Ratio", "Packed", "pw?");
System.Console.WriteLine(new System.String('-', 72));
header = false;
}
System.Console.WriteLine("{1,-22} {2,8} {3,5:F0}%   {4,8}  {5,3} {0}",
e.FileName,
e.LastModified.ToString("yyyy-MM-dd HH:mm:ss"),
e.UncompressedSize,
e.CompressionRatio,
e.CompressedSize,
(e.UsesEncryption) ? "Y" : "N");


}
}

Edited To Note: DotNetZip used to live at Codeplex. Codeplex has been shut down. The old archive is still available at Codeplex. It looks like the code has migrated to Github:

• https://github.com/DinoChiesa/DotNetZip. Looks to be the original author's repo.
• https://github.com/haf/DotNetZip.Semverd. This looks to be the currently maintained version. It's also packaged up an available via Nuget at https://www.nuget.org/packages/DotNetZip/

In such case you will need to parse zip local header entries. Each file, stored in zip file, has preceding Local File Header entry, which (normally) contains enough information for decompression, Generally, you can make simple parsing of such entries in stream, select needed file, copy header + compressed file data to other file, and call unzip on that part (if you don't want to deal with the whole Zip decompression code or library).

With .Net Framework 4.5 (using ZipArchive):

using (ZipArchive zip = ZipFile.Open(zipfile, ZipArchiveMode.Read))
foreach (ZipArchiveEntry entry in zip.Entries)
if(entry.Name == "myfile")
entry.ExtractToFile("myfile");

Find "myfile" in zipfile and extract it.

Here is how a UTF8 text file can be read from a zip archive into a string variable (.NET Framework 4.5 and up):

string zipFileFullPath = "\{\{TypeYourZipFileFullPathHere}}";
string targetFileName = "\{\{TypeYourTargetFileNameHere}}";
string text = new string(
(new System.IO.StreamReader(
System.IO.Compression.ZipFile.OpenRead(zipFileFullPath)
.Entries.Where(x => x.Name.Equals(targetFileName,
StringComparison.InvariantCulture))
.FirstOrDefault()
.Open(), Encoding.UTF8)
.ReadToEnd())
.ToArray());

the following code can read specific file as byte array :

using ZipArchive zipArchive = ZipFile.OpenRead(zipFilePath);
foreach(ZipArchiveEntry zipArchiveEntry in zipArchive.Entries)
{
if(zipArchiveEntry.Name.Equals(fileName,StringComparison.OrdinalIgnoreCase))
{
Stream stream = zipArchiveEntry.Open();
using MemoryStream memoryStream = new MemoryStream();
await stream.CopyToAsync(memoryStream);
return memoryStream.ToArray();
}
}