ZipCrc VB.NET WinRT Reference Documentation


Current Version:

Calculate a Zip CRC checksum for a file or in-memory data.

Object Creation

Dim obj As New Chilkat.ZipCrc()


LastMethodSuccess As Boolean

Indicate whether the last method call succeeded or failed. A value of True indicates success, a value of False indicates failure. This property is automatically set for method calls. It is not modified by property accesses. The property is automatically set to indicate success for the following types of method calls:

  • Any method that returns a string.
  • Any method returning a Chilkat object, binary bytes, or a date/time.
  • Any method returning a standard boolean status value where success = True and failure = False.
  • Any method returning an integer where failure is defined by a return value less than zero.

Note: Methods that do not fit the above requirements will always set this property equal to True. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.



Sub BeginStream()

Provides a way to calculate a CRC by streaming the data a chunk at a time. An application would start by calling BeginStream. Then it would add data by calling MoreData for each additional chunk. After the last chunk has been processed, the EndStream method is called to return the CRC.

Function CalculateCrc(ByVal data As Byte()) As UInteger

Calculates a 32-bit CRC for in-memory byte data. This is the 32-bit CRC that would be found in a Zip file header if a file containing the data was added to a zip archive. Returns the CRC32 of the data.

Function EndStream() As UInteger

Finalizes and returns the Zip CRC value calculated by calling BeginStream followed by multiple calls to MoreData.

<Awaitable> Function FileCrcAsyncAsync(ByVal path As String) As IAsyncOperation(Of UInteger)

Calculates the CRC32 of a file. The data contained in the file is streamed for the calculation to keep the memory footprint small and constant. Returns the CRC32 of the file.

Sub MoreData(ByVal data As Byte())

Adds additional data to the CRC currently being calculated. (See BeginStream for more information.)

Function ToHex(ByVal crc As Integer) As String

Converts a 32-bit integer to a hex string.

Returns Nothing on failure