Visual Basic Code of the Week (COTW)
Issue #12
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Requirements for this Issue

The source code in this issue is designed for all versions of Visual Basic.

In this Issue

This issue introduces an additional string handling/management routine. The routine allows you to take a delimited string (example: "123,433,566,112,2,4,111") and convert it to an array. Some scenarios where this technique would be useful is during data import/export routines, simple flat-file database management and easy storage for arrays. In the next issue we will discuss converting an array into a string that can be used by this routine.


Public Sub StringToGenericArray(sData As String, vArray As Variant, ByVal sDelimiter As String)


Return Value

None unless an error occurs. If an error occurs this routine will raise the error to the calling subroutine. The typical error that will be returned is a Type Mismatch (error 13) when an array of a certain data type is passed and the data in the string does not match that data type.

Sample Usage

We will demonstrate two examples of this routine. The first one will be a successful use of the routine and the second will show what happens when the array data type does not match the data contained in the data string. Example 1

    Dim sData As String
    Dim aData() As Long

    sData = "1,5,33,7,332"
    StringToGenericArray(sData, aData, ",")

The resulting array (aData) will contain 5 elements: the numbers 1, 5, 33, 7 and 332. Example 2

    Dim sData As String
    Dim aData() As Long

    On Error Goto Handler
    sData = "1,5,Dave,7,332"
    StringToGenericArray(sData, aData, ",")
    ..  Do whatever you need to do with the array ..
    Exit Sub

    MsgBox "Error " & Err.Number & " " & Err.Description
    Exit Sub

An error will occur and be raised. In this example you will see a Message Box appear with the error information in it.

Source Code

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Comments on the Source Code

We have used a technique that we call pre-allocate for allocating the elements in our array. Since we are using the redim preserve feature which can take a significant amount of time to execute we attempt to call it as little as possible. What this routine does is pre-allocate 100 elements at the start of the routine. If there are less than 100 elements found in this routine, the redim preserve function will only execute once (upon leaving this routine). If there are more than 100 elements found, additional elements are added in chunks of 25. Overall this should help minimize the calls to redim preserve which will help make this routine faster.


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