VB.net - Define what set to trigger based on the last textchanged event

In php and javascript I can do something like this

If ($a == 1){
  $set_num = 1
} Else {
  $set_num = 2
}

textbox_ . $set_num = "Some text here"
checkbox_ . $set_num = "Some text here"
radio_ . $set_num = "Some text here"

How can I do this in vb.net?

In my design page I have many textbox, checkbox and other things. What I want is to create a short code (Short as possible) so when the user types in a certain textbox I will know what schedule to activate so every time the user clicks the send button the system will just send the set that has a last text_change.

This is my code in vb.net, but it's not working

    Dim Set_Num As String

    If Cb_Set_1.Checked = True Then
        Set_Num = 1
    End If


    If "Cb_Sat_" & "Set_Num.Checked" = True Then
        b = 4
    Else
        b = 0
    End If