Adding dynamic Button and changing its Property text. VB.NET - vb.net

Question

I have this problem by changing the text of added dynamically button.
I want to change the button text from "Select" to "Update".
this is my code.
dim oButton as button
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim dr As SqlDataReader
Dim cn As SqlConnection = New SqlConnection("Data Source=server;Initial Catalog=testDB;Integrated Security=True;MultipleActiveResultSets=true;")
cmd.Connection = cn
cmd.CommandType = CommandType.StoredProcedure
cmd.CommandText = "votecand"
Dim stream As New MemoryStream()
cn.Open()
dr = cmd.ExecuteReader
If dr.HasRows = True Then
while dr.read
oButton = New Button
oButton.Enabled = True
oButton.Font = New Font("Tahoma", 11, FontStyle.Regular)
oButton.Location = New Point(ButtonNumber * 30, ButtonNumber * 30)
oButton.Name = "MyButton" & ButtonNumber.ToString
oButton.Size = New Size(134, 34)
oButton.BackColor = Color.MediumSeaGreen
oButton.FlatStyle = FlatStyle.Flat
oButton.ForeColor = Color.White
oButton.Text = "Select"
oButton.Visible = True
oButton.Dock = DockStyle.Bottom
oButton.Tag = ButtonNumber
AddHandler oButton.Click, AddressOf onButtonClick
Me.Controls.Add(oButton)
End while
End if
End sub
this code is MyFunc Function
Private Sub MyFunc(ByVal ButtonNumber As Integer)
Dim cn As SqlConnection = New SqlConnection("Data Source=server;Initial Catalog=testDB;Integrated Security=True;MultipleActiveResultSets=true;")
Dim command As New SqlCommand
command = New SqlCommand("select first_name,middle_name,last_name,position,gender,course,year_level,aff,student_id from tbl_cand where id=#id", cn)
command.Parameters.AddWithValue("#id", SqlDbType.VarChar).Value = ButtonNumber.ToString
Dim dt As New DataTable()
Dim adapater As New SqlDataAdapter(command)
adapater.Fill(dt)
Dim fname As String = dt.Rows(0).ItemArray(0).ToString
Dim mname As String = dt.Rows(0).ItemArray(1).ToString
Dim lname As String = dt.Rows(0).ItemArray(2).ToString
Dim gender As String = dt.Rows(0).ItemArray(3).ToString
Dim course As String = dt.Rows(0).ItemArray(4).ToString
Dim year As String = dt.Rows(0).ItemArray(5).ToString
Dim aff As String = dt.Rows(0).ItemArray(6).ToString
Dim studid As String = dt.Rows(0).ItemArray(7).ToString
lblfname.Text = fname
lblmname.Text = mname
lbllname.Text = lname
lblgender.Text = gender
lblyear.Text = year
lblmajor.Text = course
lblaff.Text = aff
connect()
sql = "INSERT INTO tbl_castvote(can_id,fname,img,student_id)"
sql = sql + "VALUES(#canid,#fname,#pos,#img,#voterid,#stdid)"
cmd = New SqlCommand(sql, con)
With cmd
.Parameters.AddWithValue("canid", studid)
.Parameters.AddWithValue("fname", fname)
Dim ms As New MemoryStream()
pb.Image.Save(ms, pb.Image.RawFormat)
Dim data As Byte() = ms.GetBuffer()
Dim p As New SqlParameter("#img", SqlDbType.VarBinary)
p.Value = data
.Parameters.Add(p)
.Parameters.AddWithValue("stdid", studentid.Text)
End With
If MsgBox("You have selected" & " '" & fname & " " & mname & " " & lname & "' " & "as" & " '" & pos & "' ", vbOKCancel + vbInformation, "Voting System") = vbOK Then
cmd.ExecuteNonQuery()
oButton.Text = "Update" --> this line is my problem. Can't change the oButton.text "Select" to "Update"
End If
End Sub
and this is my button click handler
Private Sub onButtonClick(ByVal sender As System.Object, ByVal e As System.EventArgs)
Dim ButtonNumber As Integer
If CType(sender, Button).Tag IsNot Nothing Then
If Integer.TryParse(CType(sender, Button).Tag.ToString, ButtonNumber) Then
MyFunc(ButtonNumber)
End If
End If
End Sub
pls help me. thank you

Answer 1

A couple of issues. You need to increment your ButtonNumber value inside your loop:
while dr.read
ButtonNumber += 1
oButton = New Button
oButton.Name = "MyButton" & ButtonNumber.ToString
Then in your function, you have to find your button to update it:
cmd.ExecuteNonQuery()
Dim btn As Button = Me.Controls.OfType(Of Button).
Where(Function(x) x.Name = "myButton" & btnNumber.ToString).
FirstOrDefault()
If btn IsNot Nothing Then
btn.Text = "Update"
End If
Change your function parameter to be unique:
Private Sub MyFunc(btnNumber As Integer)

Answer 2

You are using one reference for multiple buttons. You have two options from the above code.
1. Save your added button references in a list
Private Buttons As List(of Button)
Before you start your loop
Buttons = New List(of Button)
in your loop
Dim oButton = New Button
ButtonNumber = Buttons.Count '<-- use the collection count as the number
...blah blah blah...
Buttons.Add(oButton)
Then in myFunc simply use
Buttons(ButtonNumber).Text = "whatever"
2. If this is the only place you reference it, pass the sender along instead.
Private Sub MyFunc(Byref Pressed_Button as Button, ByVal ButtonNumber As Integer)
...blah blah blah...
Pressed_Button.Text = "whatever"
End Sub
Private Sub onButtonClick(ByVal sender As System.Object, ByVal e As System.EventArgs)
Dim PressedButton as Button = CType(sender, Button)
Dim ButtonNumber As Integer
If PressedButton.Tag IsNot Nothing Then
If Integer.TryParse(PressedButton.Tag.ToString, ButtonNumber) Then
MyFunc(PressedButton, ButtonNumber)
End If
End If
End Sub
There are also ways to search for the control by name, but keeping your own index is more efficient.