What's the best way to iterate through multiple controls? (Resolved)

Hi all,

I anticipate having to build a form with well over 100 controls, mainly labels that will emulate LED's. I need some way to iterate through many controls at a time, but I'm really not getting anywhere :(

I was thinking of some kind of for each...next loop, but a search of these forums produced zero results, and none of my VB .NET books mention it other than in passing. Presumably it isn't the way to go about this. Plus I spent several hours yesterday playing about in VS and I kept getting error after error, even using code copied and pasted from MSDN Library, so I 'm obviously not understanding this at all.

So, can any of you good people point me in the right direction here please?. If there's one thing that I miss it's the old control array in VB6 - at least I knew how to use that.

You can create control arrays...

VB Code:

Private MyLabels() As Label = New Label() {Label1, Label2, Label3}
 
    Private Sub Form1_Load(ByVal sender As System.Object, _
                           ByVal e As System.EventArgs) _
                           Handles MyBase.Load
 
        For Each lbl As Label In MyLabels
            MsgBox(lbl.Text)
        Next
 
    End Sub

HI,

Maybe I'm missing the point but why does he need a Control Array? All he is asking is to iterate through a large number of controls and that has been discussed many times in this forum. He can check which type of control is being passed and, by using the Tag property, he can even isolate controls of the same type into different groups. e.g.

VB Code:

Dim ctr As Control
        For Each ctr In Controls
            MessageBox.Show(ctr.Name)
        Next

or

VB Code:

Dim ctr As Control
        For Each ctr In Controls
          If TypeOf ctr Is TextBox Then
                MessageBox.Show(ctr.Name)
            End If
        Next

or

VB Code:

Dim ctr As Control
        For Each ctr In Controls
          If TypeOf ctr Is TextBox Then
             Select Case ctr.Tag
                case = "Red"
                  ctr.forecolor=Color.Red
                case Else
                   ctr.forecolor=color.White              
              End Case
            End If
        Next

HI supersparks,

I do not understand when you say thee is noting in this forum on the subject, there are dozens of threads on it. What are you searching under?

Hi Taxes, I searched under "for each" which returned zero results, and then I tried "for each next" which brought up dozens of results for for next loops. Usually I'm pretty good at searching, being a mod on another forum using vBulletin, but this one defeated me :D If you could suggest another term I'd be grateful, I get a lot of help from the old threads.

It's the lack of results that had me thinking that it wasn't the way to go about this.

Thanks for the help so far guys, that's given me something to get started with anyway.

I'm thinking of putting the related labels into groupboxes, will that make things easier or harder?

Hi SuperSparks,

Try searching under "Looping through Controls" but only look at the VB.NET posts.

Iin theory putting the labels into groupboxes should help, but I could not iterate through controls contained in another control. I don't understand this as both forms and controls are all objects.

Why don't you just use the Tag property to group them?

Even that only found 10 threads. I'm surprised that this hasn't been discussed more.

Well I tried an example anyway, on a test form with a Groupbox and 3 NumericUpDowns that I happened to have handy.

VB Code:

Dim nud As NumericUpDown
        For Each nud In Me.GroupBox2
 
        Next

And what I got for my pains, in Intellisense, was:

Quote:

---

Expression is of type "System.Windows.Forms.Groupbox", which is not a collection type

---

I just don't know why I'm struggling so much with this, but even the examples from MSDN Library, cut & pasted throw exceptions. Do I need to import something?

Hi,

As I told you, I could not iterate through the controls contained in another control.

With acknowledgements to BrownMonkey, if you want to lightup a control, say by setting it's backcolor to a predetermined colour, then all you have to do is set the Tag property of the control to the desired VB.NET color ( say enter "Red" in textbox1.Tag) and then:

VB Code:

Dim ctr As Control
        Dim sCol As String
             For Each ctr In Controls
                If TypeOf ctr Is TextBox Then
                   IfCstr(ctr.Tag)<>"" then
                        sCol = CStr(ctr.Tag)
                        ctr.BackColor = Color.FromName(sCol)
                    End If
                End If
            Next

In this context, the colour entered in the Tag property is case insensitive.

Is that what you are looking for?

I'd go with crptcblade's idea and put them in the array, much easier to change all the properties at once and stuff.

Quote:

---

Originally posted by Ideas Man
I'd go with crptcblade's idea and put them in the array, much easier to change all the properties at once and stuff.

---

I'd be interested to know why you consider it easier.

I think you would use virtually the same code in either case and you don't bother with setting up the array.

What am I missing, please? (apart from a brain)

Hi,

With acknowledgements to CyberHawke,

VB Code:

Dim ctl1 As Control, ctl2 As Control
For Each ctl1 In Me.Controls
    If ctl1.Name = "Panel1" Then
        For Each ctl2 In ctl1.Controls
            If ctl2.Name = "Button1" Then MessageBox.Show("Found It!")
        Next
    End If
Next

will let you iterate through contained controls.

EDIT, CyberHawke has just come up with

VB Code:

Dim ctl As Control
        For Each ctl In Me.Panel1.Controls
            MessageBox.Show(ctl.Name)
        Next

I posted code that does something like you are asking:
http://www.vbforums.com/showthread.p...hreadid=287282

Many thanks people, at last I'm getting somewhere :)

Although crptcblade's idea will undoubtedly be very useful for other projects, I don't fancy it much for this one, if only to save my poor old fingers from all that typing :D

Those last two examples from Taxes/ CyberHawke worked perfectly, I think I'll be able to do something with those.

And I'll do some investigating of tags, those are a new one for me and I know nothing about them.