VB.NET

File Read Blocks

Demonstrates how to read a file in fixed-size blocks (except for the very last block). VB.NET

Dim success As Boolean = False

' Demonstrates how to read a file in blocks,
' which can be useful when uploading to cloud storage
' services such as Azure, S3, Google, etc.

' For this example, we're simply writing the blocks
' to an output file, and then checking to see if the
' resulting file contents equals the original file contents.

Dim dataBlock() As Byte

Dim facSrc As New Chilkat.FileAccess
Dim facDest As New Chilkat.FileAccess

Dim srcPath As String = "qa_data/xml/hamlet.xml"
Dim destPath As String = "qa_output/hamletOut.xml"

success = facSrc.OpenForRead(srcPath)
success = facDest.OpenForWrite(destPath)
' Assuming success for the example..

' How many 1024-byte blocks?  (Including 1 for the last partial block)
Dim numBlocks As Integer = facSrc.GetNumBlocks(1024)

Dim i As Integer = 0
While (i < numBlocks)
    dataBlock = facSrc.ReadBlock(i,1024)
    If (facSrc.LastMethodSuccess <> True) Then
        Debug.WriteLine(facSrc.LastErrorText)
        Exit Sub
    End If

    success = facDest.FileWrite(dataBlock)
    If (success <> True) Then
        Debug.WriteLine(facDest.LastErrorText)
        Exit Sub
    End If

    i = i + 1
End While

facSrc.FileClose()
facDest.FileClose()

Dim bEqual As Boolean = facSrc.FileContentsEqual(srcPath,destPath)
If (bEqual <> True) Then
    Debug.WriteLine("Something went wrong!")
    Exit Sub
End If


Debug.WriteLine("File successfully copied by blocks.")