New Article: Mimicking VB6 Control Arrays in VB.NET

[sde]

Geoff Alexander, aka PUN1SH3R, has contributed a VB.NET article demonstrating how to mimick a control array since MS has decided to take that out of VB.NET.

You can check out the article here.

[tvqpriqphh]

The code sample doesn't describe a control array, rather "programmatic addressing". This code snippet does exactly the same thing (in a less rediculous fashion):

select case txtwhotext.text
    case "1"
        textbox1.text = "1"
    case "2"
        textbox2.text = "2"
    case "3"
        textbox3.text = "3"
    case "4"
        textbox4.text = "4"
end select

if you want an array of controls, try something like this:

' this is a class/form instance variable
' use nothing as a place holder for element zero in the zero based array
dim ca as control() = new control() {nothing, textbox1, textbox2, _
textbox3, textbox4}

sub dosomething()
    ' get the user specified index
    dim index as integer = cint(textwhotext.text)

    ' put the user specified message into that textbox
    ca(index).text = textwhotext.text

end sub

note that this really only gets you halfway home -- you now have a way to translate an integer index into a control object reference -- how do you convert a control object reference into an integer index?

function getindex(c as control) as integer
    for i as integer = 1 to ca.length-1
        if c is ca(i) then
            return i
        end if
    next
    throw new applicationexception("control reference not found")
end function

now we can have "control array" based events like this (having to manually bind events makes maintaining this code a bit ugly)

sub click_handler(sender as object, ea as eventargs) handles _
textbox1.click, textbox2.click, textbox3.click, textbox4.click
    dim i as integer = getindex(sender)
    ca(i).text = "you clicked me"

end sub

note that .net sort of obsoletes the need for control arrays, because you could just have easily defined click_handler as follows:

sub load
    addhandler textbox1.click, addressof (click_handler)
    addhandler textbox2.click, addressof (click_handler)
    addhandler textbox3.click, addressof (click_handler)
    addhandler textbox4.click, addressof (click_handler)

end sub

sub click_handler(sender as object, ea as eventargs)
    ctype(sender, control).text = "you clicked me"

end sub

[CardsFan]

Originally Posted by sde

Geoff Alexander, aka PUN1SH3R, has contributed a VB.NET article demonstrating how to mimick a control array since MS has decided to take that out of VB.NET.

You can check out the article here.

This code works GREAT. I modified it to work in a group box with an array of pictureboxes.

I have been looking all over the web for something simple to do this and either they say it can't be done or you get some convoluted code. This is a nice simple way that I can't believe no one else has posted.

There does need to be 1 minor change - in the 2nd FOR Next loop, it should be Controls.Count - 1 (Count is number of controls, but array starts at zero)

My modified code

For x As Integer = 7 To 1 Step -1
            For c As Integer = 0 To gbFanny.Controls.Count - 1
                If TypeOf (gbFanny.Controls(c)) Is PictureBox Then
                    Dim pbname As String = "pbFanny" & x.ToString
                    If gbFanny.Controls.Item(c).Name = pbname Then
                        Dim pb As PictureBox = gbFanny.Controls(c)
                        pb.Image = arCards(x)
                        'Exit For
                    End If
                End If
            Next
        Next

I think the previous poster misunderstood the point of the code. Of course you wouldn't do that for 4 simple text boxes but it's a great example of how to use control arrays - especially useful for Group Boxes that for some reason are unusually hard to manage.