VB.Net How can I loop an If statement with multiple variables?

Question

So if I have lets say 10 textboxes I need to fill I have to repeat a loop 10 times and each time add to a different text box. Right now I have something like this:

    If i = 0 Then
        Shift0 = endTime - startTime
        textStart0.text = startTime
        textEnd0.text = endTime
        chkBox0.checked = True
    End If

I have I repeating like that 8 more times to make 9. I want to make it so that the loop would increase the number from 0-9 every time it goes through

    If i = (x) Then
        Shift(x) = endTime - startTime
        textStart(x).text = startTime
        textEnd(x).text = endTime
        chkBox(x).checked = True
    End If
    x = x + 1

How can I put it in the loop so that the number in the name of the object increased with every loop?

I think you want arrays - see e.g. msdn.microsoft.com/en-us/library/wak0wfyt.aspx. You should try to keep data out of your variable names. — jonrsharpe
– jonrsharpe, Commented Aug 11, 2014 at 11:02
The arrays could have the data in them yes but i want to display that data in a set of textboxes. However instead of writing out each text box I want the loop to do it for me and adding a number to the textbox name like TextBox(x=1), TextBox(x=2).... etc — TensE
– TensE, Commented Aug 11, 2014 at 11:05

Grim · Accepted Answer · 2014-08-11 11:25:56Z

2

Control arrays are a thing of the past, from the VB6 days, unfortunately, as you've discovered, they can still have their uses! Try this for your loop;

For i = 0 to 9
    Shift0 = endTime - startTime                     ' Is Shift0 a control!?
    FindControl("textStart" & i).Text = startTime
    FindControl("textEnd" & i).Text = endTime
    FindControl("chkBox" & i).Checked = True
Next

With this function to help...

Private Function FindControl(pName As String) As Control
    Dim vMatches = Me.Controls.Find(pName, True)
    If vMatches IsNot Nothing AndAlso vMatches.Length > 0 Then Return vMatches(0)
    Throw New Exception("Could not find the specified control!")
End Function

Having said all that, I would strongly recommend re-thinking how your form and application work to avoid this!

answered Aug 11, 2014 at 11:25

Grim

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Comments

stato74 · Accepted Answer · 2014-08-11 11:10:36Z

1

Something like this would work

For x = 0 to 9
    Shift(x) = endTime - startTime
    textStart(x).text = startTime
    textEnd(x).text = endTime
    chkBox(x).checked = True
next x

answered Aug 11, 2014 at 11:10

stato74

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Comments

Jxx · Accepted Answer · 2014-08-11 12:19:12Z

0

You can use the Controls property of a Control with an index. If your form contains exactly and only 10 textboxes, this will work fine:

For i as Integer = 1 to 10
    Form1.Controls(i).Text = "Box " + i.ToString()
Next

If you have other controls in the form you have no guarantee over the index (you can't reply on 1 to 10 being the textboxes as your design progresses). Therefore, I'd recommend you put them inside a panel and refer to this panel's Controls:

For i as Integer = 1 to 10
    Panel1.Controls(i).Text = "Box " + i.ToString()
Next

To learn more about loops in VB.NET, start here: http://www.tutorialspoint.com/vb.net/vb.net_loops.htm

answered Aug 11, 2014 at 12:19

Jxx

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5 Comments

Grim Over a year ago

That is just such bad practice... I'm speechless!!

Jxx Over a year ago

It's certainly more efficient than FindControl, and it's not reliant upon a control's name. There isn't a "good practice" answer to this "bad practice" problem.

Grim Over a year ago

That's fair enough - I agree it's not efficient. But then the OPs problem of putting the same data into 10 sets of controls isn't exactly efficient in the first place. And I also agree that the problem is bad practice. Still, iterating controls in a random order, not casting to the correct control types and starting indexes at 1 instead of zero seem worse to me :P

Jxx Over a year ago

I don't have enough rep to comment on your answer, but if you passed a "searchable" control argument to FindControl (a panel), you wouldn't have to search the whole form. (In both answers, logical sorting is the problem still... I can't think of a better way than sorting them by vertical position!)

Grim Over a year ago

I wouldn't waste any more time worrying about it - it's going to be another one of those questions that the OP never closes and will just sit like this for years...

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