Creating a Server Component with VB - Redesigned - Part 2

Before you look at the code that combines all the various code sections we covered, there''''s one issue that needs to be mentioned. Although the example program is not in need of optimization, you may find that concatenating many strings within looping code can noticeably slow down your method''''s efficiency. String buffer can significantly increase processing speed by creating a large string and inserting other shorter strings with the Mid$() method.

Since you can find a more complete explanation of string buffering (see "How To Utilize String Buffering Within A VB Component" at http://www.dougdean.com for an article on string buffering), I''''ll just briefly review the buffer code and demonstrate how it can be used to construct the return string used in the ShowNotes() method.

To use the string buffering technique with our example method, we''''ll need a second method. This second method, named S1 in the code below, will be used to combine all the strings and variables we concatenated in the last code section. The code below uses cryptic method and variable names (S1, S2, S3) for string buffering in order to make the code more concise. Again, refer to the string-buffering article mentioned above for further details.

This code section uses the ShowNotes() method structure, without any extraneous string-buffering code, to exemplify building a simple string by sending string fragments to the S1() method.

''''\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ 
''''                       ShowNotes CLASS
''''\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ 
Public Function ShowNotes(ByVal lngNoteID As Long, _
	Optional ByVal intStyleID As Integer = 0, _
	Optional ByVal strURL As String = "NoteExample.asp", _
	Optional ByVal strDbConnectionString As String = "NotesDSN") As String
                   
    ''''///// String buffering variables and values
    Dim S2 As String
    S2 = String$(65536, Chr(0))
    Dim S3 As Long
    S3 = 0 

    S1 S2, S3, "This is an "
    S1 S2, S3, "example of "
    S1 S2, S3, "using the string-buffering "
    S1 S2, S3, "method in place of "
    S1 S2, S3, "concatenation"


    ''''///// SEND BACK CONSTRUCTED TEXT IN BUFFER ////////////////////
    ShowNotes = Left$(S2, S3)


End Function
''''\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ 


''''\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ 
''''                        STRING BUFFERING
'''' S1 = Method / S2 = Buffer / S3 = Buffer Length
''''\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ 
Private Sub S1(ByRef S2 As String, ByRef S3 As Long, ByVal AddString As String)
 
    Dim strTemp As String
    Dim lngLoop As Long
        
    ''''///// Empty strings will cause a fatal error if not eliminated
    If Not Trim$(AddString) = "" Then
    
        ''''[1]///// DOES BUFFER NEED TO BE INCREASED?
        If S3   Len(AddString) > Len(S2) Then
            ''''///// STORE S2
            strTemp = S2
            ''''///// Increase memory storage bytes
            Do
                lngLoop = lngLoop   1
                If (Len(S2)   (65536 * lngLoop)) >= (S3   Len(AddString)) Then
                    Exit Do
                End If
            Loop
            ''''///// Resize buffer
            S2 = String$(Len(S2)   (65536 * lngLoop), Chr(0))
            ''''///// RESTORE S2
            Mid$(S2, 1, S3) = strTemp
        End If
        
        ''''[2]///// ADD STRING TO BUFFER
        Mid$(S2, S3   1, Len(AddString)) = AddString
        ''''[3]///// SET STRING LENGTH IN BUFFER
        S3 = S3   Len(AddString)
        
    End If
    
End Sub
''''\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\


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