Expands the contents of a previously specified file.
OutputFile, [CompressionType] )
- A string value that specifies the name of the file to be expanded. The file must
exist, and it must be a file that was created by a previous call to
the CompressFile method. An error will be returned if the
file cannot be accessed, if it specifies a character device such as
the console, or the if the data is not in a recognizable
- A string value that specifies the name of the file that will contain the expanded data.
If the file exists, it must be a regular file that can be opened
for writing by the current process and will be overwritten. If the
file does not exist, it will be created. An error will be returned
if a character device, such as the console, is specified as the
- A numeric value which determines the algorithm that was used to
compress the data. One of the following values may be specified. If
this argument is not specified, the Deflate algorithm is used. If
the compression type specified by this argument does not match the
actual compression algorithm used to compress the file, an error
will be returned.
||A compression algorithm that combines LZ77 algorithm for
creating common substrings and Huffman coding to process the
different frequencies of byte sequences in the data stream.
Deflate is widely used by compression software.
||A compression algorithm that rearranges blocks of data in
sorted order and then uses Huffman coding to process
different frequencies of data within the block.
Burrows-Wheeler compression provides a better compression
ratio than the Deflate algorithm, however it requires more
resources to perform the compression.
This method returns a value of zero if the file was successfully
compressed. A non-zero return value specifies an error code which
indicates the reason for the failure.
The ExpandFile method expands the contents of a previously
It is permitted to specify an empty string as the output
file name. In this case, the control will create a temporary file in
the directory specified by the TEMP environment variable. After the
file has been expanded, the OutputFile property will be set
the name of the temporary file that has been created. It is the
responsibility of the application to delete this temporary file after
it is no longer needed.
Note that this method can only expand files that were compressed
using the control. It cannot expand the contents of a file stored in
an archive format such as PKZip or WinZip.