Dynamic ID name in ASP.NET VB.NET

Question

I have about 20 asp:labels in my ASP page, all with ID="lbl#" , where # ranges from 0 to 22. I want to dynamically change what they say. While I could write

lbl1.Text = "Text goes here"

for all 23 of them, I'd like to know if there is a way to loop through all of them and change their text.

I thought of creating an array with all my labels, and then just do a For Each loop, but I also have to check if the element exists with IsNothing before I change its text, so I got stuck there.

If anyone can help me, I'd really really appreciate it!

Thank you so so much for your help!!

Answer 1

You can dynamically look up controls on the page by using the System.Web.UI.Page.FindControl() method in your Page_Load method:

Dim startIndex As Integer = 0
Dim stopIndex As Integer = 22

For index = startIndex To stopIndex
    Dim myLabel As Label = TryCast(FindControl("lbl" + index), Label)

    If myLabel Is Nothing Then
        Continue For
    End If

    myLabel.Text = "Text goes here"
Next

Answer 2

Something like this may work, but you would likely need to tweak it (its from memory, so its not exactly 100% syntactically correct)

For Each _ctl as Control In Me.Controls()
  If (TypeOf(_ctl) Is Label) = False Then
    Continue For
  End If

  'add additional filter conditions'

  DirectCast(_ctl, Label).Text = "Text Goes Here"
Next

You can also do something similar on the client side using jQuery selectors .