How do I add buttons with event handlers to a form dynamically? - vb.net

Question

Is it possible to do this dynamically? How?
Code:
Public Class Form1
Dim c(40) As Integer
Dim IMG As PictureBox
Dim lbl_n(40) As Label
Dim lbl_pr(40) As Label
Dim lbl_ref(40) As Label
Dim lbl_dim(40) As Label
Dim lbl_col(40) As Label
Dim btn_add(40) As Button
Dim btn_rmv(40) As Button
Dim tb_qt(40) As TextBox
AddHandler btn_add(0).Click, AddressOf btn_add0_Click
AddHandler btn_add(1).Click, AddressOf btn_add1_Click
[...]
AddHandler btn_add(40).Click, AddressOf btn_add40_Click
Public Sub btn_add0_Click(ByVal sender As Object, ByVal e As System.EventArgs)
c(0) = c(0) + 1
tb_qt(0).Text = c(0)
End Sub
Public Sub btn_add1_Click(ByVal sender As Object, ByVal e As System.EventArgs)
c(1) = c(1) + 1
tb_qt(1).Text = c(1)
End Sub
[...]
Public Sub btn_add40_Click(ByVal sender As Object, ByVal e As System.EventArgs)
c(40) = c(40) + 1
tb_qt(40).Text = c(40)
End Sub
These are the images with program running (they are edited):
Form1
Form2
I want to dynamically, because I could use more than 40 products! And I need to do 40 addhandlers, so that more 40 to remove!
How can I do that?

Answer 1

Yes, You can do that dynamically.
In this example, I put those buttons and textboxes into Panel.
There is example with comments which line is for what :
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
'dynamically adding buttons (so You don't need create every button separately)
For x = 1 To 40
Dim btn As New Button 'create new button
btn.Name = "btn_add" & x.ToString 'set ID for button (example: btn_add1, btn_add2, ... btn_add40)
btn.Text = "+" 'set button text
btn.Tag = x.ToString 'set button NO. for finding corrent textbox whos belong to this button (for example: tb_qt1 belong to buttons btn_add1 and btn_rem1)
btn.Width = 24 'this is for styling
btn.Top = (x * btn.Height) + 3 'for styling, too. Top poistion of button
btn.Left = 0 'for styling, too. Left position of button
AddHandler btn.Click, AddressOf btnAdd_Click 'creating sub called btnAdd_Click (this sub will handle all, in this case 40, buttons)
Panel1.Controls.Add(btn) 'for this example I put buttons and textboxes into panel (autoscroll set to True)
btn = New Button 'same thing just for remove button
btn.Name = "btn_rem" & x.ToString
btn.Text = "-"
btn.Tag = x.ToString
btn.Width = 24
btn.Top = (x * btn.Height) + 3
btn.Left = btn.Width + 3
AddHandler btn.Click, AddressOf btnRem_Click 'creating sub called btnRem_Click (this sub will handle all, in this case 40, buttons)
Panel1.Controls.Add(btn)
Dim txt As New TextBox 'same thing for textboxes
txt.Name = "tb_qt" & x.ToString
txt.Text = "0"
txt.Tag = x.ToString
txt.Top = (x * btn.Height) + 3
txt.Left = btn.Left + btn.Width + 3
txt.TextAlign = HorizontalAlignment.Right
Panel1.Controls.Add(txt)
Next
End Sub
Public Sub btnAdd_Click(sender As Object, e As EventArgs)
Dim btn As Button = DirectCast(sender, Button) 'detect which button clicked. You can add line: MsgBox(btn.Name) to see what happening
Dim txt As TextBox = Panel1.Controls.Find("tb_qt" & btn.Tag.ToString, True)(0) 'find textbox which belong to this button. this is why set .Tag into buttons
txt.Text = CInt(txt.Text) + 1 'just do math and change value, by adding one(1), in textbox (by this way I avoid using Your Dim c(40) As Integer)
End Sub
Public Sub btnRem_Click(sender As Object, e As EventArgs)
Dim btn As Button = DirectCast(sender, Button) 'same thing like for btnAdd_Click, but we doing subtract for one(1) value in textbox
Dim txt As TextBox = Panel1.Controls.Find("tb_qt" & btn.Tag.ToString, True)(0)
txt.Text = CInt(txt.Text) - 1
End Sub
Because I use panel like container for all those buttons and textboxes, You have to set AutoScroll=True for panel.
I hope so You will understand how it's work for start.