"Optional" Array Parameters

[Queez]

I've had a good look around and no-one seems to have mentioned this, which leads me to believe that I may be missing something simple.

Basically, is there a way I can do the following, and if so, how?:

Sub ResolveArrays(ByVal array1() As String, ByVal valueX As String, _
  Optional ByVal array2() As String = {""}, Optional ByVal retry As Boolean = False)
    [I]' Code to take array1 and compare each value to valueX, [/I]
   [I] ' if no value is found, either exit or[/I]
   [I] ' (optionally) compare the second array to valueX if the retry flag is set[/I]
Exit Sub

At the moment, VS2005 is throwing an error which is not allowing me to add the optional array2 to the parameters.

Of course, there are other ways I can do this, but it's bugging me now - are optional arrays not allowed?

(For an example of where the above could be used: comparing a specific value to a list of words then, if not found, comparing it to a list of common mistakes)

[Killer42]

...
At the moment, VS2005 is throwing an error which is not allowing me to add the optional array2 to the parameters.

What's the error?

[Queez]

Sorry, I think it was me being silly.

[Killer42]

Sorry, I think it was me being silly.

Not to mention very s...l...o...w.. . :) Two and a half months to respond?

Anyway, so you've got it sorted, huh?

[cugone]

I've had a good look around and no-one seems to have mentioned this, which leads me to believe that I may be missing something simple.

Basically, is there a way I can do the following, and if so, how?:

Sub ResolveArrays(ByVal array1() As String, ByVal valueX As String, _
  Optional ByVal array2() As String = {""}, Optional ByVal retry As Boolean = False)
    [I]' Code to take array1 and compare each value to valueX, [/I]
   [I] ' if no value is found, either exit or[/I]
   [I] ' (optionally) compare the second array to valueX if the retry flag is set[/I]
Exit Sub

At the moment, VS2005 is throwing an error which is not allowing me to add the optional array2 to the parameters.

Of course, there are other ways I can do this, but it's bugging me now - are optional arrays not allowed?

(For an example of where the above could be used: comparing a specific value to a list of words then, if not found, comparing it to a list of common mistakes)

Here's what you need:

    ''' <summary>
    ''' Compares array values to a given string.
    ''' </summary>
    ''' <param name="array1">Required. Array to compare against.</param>
    ''' <param name="valueX">Required. String value to compare.</param>
    ''' <param name="retry">Required. Whether or not to try the second, optional array.</param>
    ''' <param name="array2">Optional. Array to compare against if value in Array1 is not found and retry is set to true.</param>
    ''' <remarks>If array2.Length is greater than 10, only the first 10 elements will be evaluated.</remarks>
    Public Sub ResolveArrays(ByVal array1() As String, ByVal valueX As String, ByVal retry As Boolean, ByVal ParamArray array2() As String)
        Dim maxArray2Length As Integer = 10 'Insert maximum array2 length here
        For Each line As String In array1
            If line = valueX Then
                'Do something
            End If
        Next line
        If retry = True Then
            For i As Integer = 0 To maxArray2Length - 1
                If array2(i) = valueX Then
                    'Do something
                End If
            Next i
        End If
    End Sub

The summary, param, and remarks section is for the Intellisense.

All Optional parameters must 1) be listed last 2) contain a default value 3) must be before all required parameters 4) not be used when ParamArray is used.

ParamArray is an optional array of elements of the specified type.
Paramarray: 1) Must be declared ByVal 2) Must only be declared once 3) Must be the LAST parameter. 4)

Because ParamArray can be infinitely large, it's a good idea to limit how many elements it can have. I just inserted 10 as an arbitrary number, you can change it if need be.

[Queez]

Not to mention very s...l...o...w.. . :) Two and a half months to respond?

Anyway, so you've got it sorted, huh?

Hehe, sorry for my slow response. I actually never figured it out and had to use an alternative method. The alternative method involved re-thinking what I was doing, but it was actually much neater in the end.

All Optional parameters must 1) be listed last 2) contain a default value 3) must be before all required parameters 4) not be used when ParamArray is used.

ParamArray is an optional array of elements of the specified type.
Paramarray: 1) Must be declared ByVal 2) Must only be declared once 3) Must be the LAST parameter. 4).

Thanks Cugone, I wasn't aware of the ParamArray special command.

[cugone]

Hehe, sorry for my slow response. I actually never figured it out and had to use an alternative method. The alternative method involved re-thinking what I was doing, but it was actually much neater in the end.

Thanks Cugone, I wasn't aware of the ParamArray special command.

You're welcome, though I need to mention I made a little typo in the description. Optional parameters must be listed /after/ all required parameters, not before. And still, can not be used if you use ParamArray and vice versa.