How to: Add File to File Archive

When the file archive is opened with the ZipArchive.Read method, you cannot save it to the same file. The ZipArchive.Save method attempts to overwrite the locked file resulting in an exception.

This code snippet illustrates how you can add a file to an archive and save it with the same name as before.

public void AddFileToArchive() {
    MemoryStream stream = new MemoryStream();
    string[] sourcefiles = this.sourceFiles;
    string pathToZipArchive = "Documents\\Example.zip";

    using (FileStream fs = File.Open(pathToZipArchive, FileMode.Open)) {
        fs.CopyTo(stream);
        fs.Close();
    }
    stream.Seek(0, SeekOrigin.Begin);
    using (ZipArchive archive = ZipArchive.Read(stream, System.Text.Encoding.Default, false)) {
        foreach (string sfile in sourcefiles) {
            archive.AddFile(sfile, "/");
        }
        archive.Save(pathToZipArchive);
    }
}