'Declaration
 
Public Overloads Function OpenWrite( _
   ByVal overwrite As Boolean, _
   ByVal compressionMethod As CompressionMethod, _
   ByVal compressionLevel As CompressionLevel, _
   ByVal encryptionPassword As String _
) As Stream

'Usage
 
Dim instance As ZippedFile
Dim overwrite As Boolean
Dim compressionMethod As CompressionMethod
Dim compressionLevel As CompressionLevel
Dim encryptionPassword As String
Dim value As Stream
 
value = instance.OpenWrite(overwrite, compressionMethod, compressionLevel, encryptionPassword)

public Stream OpenWrite( 
   bool overwrite,
   CompressionMethod compressionMethod,
   CompressionLevel compressionLevel,
   string encryptionPassword
)

Parameters

overwrite

true if existing data for the item should be replaced; false if existing data should be preserved, appending new data at the end.

compressionMethod

The CompressionMethod that will be used to compress the file.

compressionLevel

The CompressionLevel that will be used when compressing the file.

encryptionPassword

The password that will be used to encrypt the file.

Return Value

The returned stream is guaranteed to be writable, but may or may not be seekable.

The file will be opened with System.IO.FileShare.None shared access.

The compression level only applies to the Deflated and Deflated64 compression methods.  It does not apply to the BZip2, BWT, or PPMd compression methods.

The PPMd algorithm uses a custom memory management system called SubAllocator. In a zip file, the memory size the SubAllocator uses is defined in the WinZip PPMd header for the compressed file and this header's value is used when decompressing the data. In general, WinZip uses 64Mb. Since the algorithm used was not optimized from the original PPMd version I revision 1, the SubAllocator initially requires the total amount of memory specified in the PPMd compressor. This means you must have at least 64 free Mb of RAM when using this compression method.

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

ZippedFile Class
ZippedFile Members
Overload List