Xceed Logo
Shop
Xceed Zip for COM/ActiveX on x86/x64 Documentation
Example topics / Compress method example for VB
    Compress method example for VB

    This example shows the use of the Compress and Uncompress methods for VB 6 users. Extra code is necessary in this example because it also shows you when and where to output the compressed code to a file, further process it by another function, or assign it to a 3rd party component property for file transfer. This is necessary because Variants are not correctly converted by VB into other types. The technique for converting the data ourselves into a format usable by commands such as VB's Get and Put is to use Byte arrays.

    To use the example, place an XceedCompression control on a form and run the following code:

    Visual Basic Copy Code

    ' The byte array which will contain the data to save or transfer:
    Dim TempByteArray() As Byte  

    ' We'll put some text to compress here:
    Dim OriginalData As Variant 

    ' Xceed Compression will place the compressed data here:
    Dim CompressedData As Variant 

    ' To uncompress the data we'll put it in this variable:
    Dim ToUncompress As Variant 

    ' Xceed Compression will place the uncompressed data here:
    Dim UncompressedData As Variant 

    ' The result codes will be placed in this variable
    Dim ResultCode As xcdCompressionError 

    OriginalData = "Text or data to compress" 

    Call XceedCompression1.License( "your license key" )

    ResultCode = XceedCompression1.Compress(OriginalData, CompressedData, True)

    ' Make sure it worked successfully, display message
    If ResultCode <> xerSuccess Then
       MsgBox "Compression unsuccessful. Error # " & Str(ResultCode) & " occurred. " & _
              "Description: " &  XceedCompression1.GetErrorDescription(ResultCode) 
    Else 
       MsgBox "Compression successful." 
    End If  

    ' Now the CompressedData variable is a Byte Array Variant, but it still cannot
    ' be assigned properly to other properties or used by the Get and Put method until
    ' we convert it to a real byte array as follows: 

    ReDim TempByteArray(1 To UBound(CompressedData)) As Byte
    TempByteArray = CompressedData 

    ' Ok, now you can do whatever you want with the compressed data located in the
    ' " TempByteArray" byte array variable (not a Variant!) 

    ' [Save, process or transfer your data here!] 

    ' Ok, now its time to decompress your saved data, so place it in the TempByteArray byte array variable. 

    ' [Load your saved or transferred compressed data here!] 

    ' Lets convert it to a Variant Byte Array before uncompressing it 

    ToUncompress = TempByteArray 

    ' Now let's uncompress the data 

    ResultCode = XceedCompression1.Uncompress(ToUncompress, UncompressedData, True) 

    ' UncompressedData variable should now contain same data as the OriginalData variable
    ' Check to see if it worked properly, display message 

    If ResultCode <> xerSuccess Then
       MsgBox "Decompression unsuccessful. Error # " & Str(ResultCode) & " occurred. " & _
              "Description: " & XceedCompression1.GetErrorDescription(ResultCode) 
    Else 
       MsgBox "Decompression successful." 
    End If 

     

     

    © Xceed Software Inc. All Rights Reserved.

    Send comments on this topic.