Is there any way for Retrieve Record Value from Table Column , Loop and Loop in vb.net - vb.net

Question

Sorry for my poor English
When the user clicks the Start button, I am trying to display all of the records from the Phone column in the Textbox1 control. I want to see all those records pass into Textbox1 While it is processing the For loop. But it is currently processing very fast so that I only see the last record in Textbox1. What i'm going wrong?
While it is processing the For loop, I change the Start button to a Stop button. So when I click the button and it currently has a Text value equal to "Stop", I want it to skip the For loop and pass the value from TextBox1 to my FirstWin. And then it should change the BtnStart.Text back to "Start"
Here's my code:
Public Class PhoneFortune
Dim CN As OleDbConnection
Dim CM As OleDbCommand
Dim DA As OleDbDataAdapter
Dim DT As New DataTable
Private Sub BtnStart_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnStart.Click
If BtnStart.Text = "Start" Then
CM = New OleDbCommand("SELECT * FROM TblPhoneNumber", CN)
DA = New OleDbDataAdapter(CM)
DA.Fill(DT)
For i = 0 To DT.Rows.Count - 1
TextBox1.Text = DT.Rows(i)("Phone")
Next
BtnStart.Text = "Stop"
End If
If BtnStart.Text = "Stop" Then
If FirstWin.Text = "" Then
FirstWin.Text = TextBox1.Text
BtnStart.Text = "Start"
ElseIf SecondWin.Text = "" Then
SecondWin.Text = TextBox1.Text
BtnStart.Text = "Start"
ElseIf ThirdWin.Text = "" Then
ThirdWin.Text = TextBox1.Text
BtnStart.Text = "Start"
End If
End If
End Sub
Private Sub PhoneFortune_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
CN = New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=database\db.accdb;Jet OLEDB:Database Password=12345;")
CN.Open()
End Sub
End Class

Answer 1

I hope we are on the same page but if u want to slow down the process for a bit u use these two lines of code within the FOR loop
System.Threading.Thread.Sleep(1000)
Me.Refresh() Where 1000 is one second(value is represented in milliseconds).
Now what is that FirstWin.Text="" etc used for? Are you trying to start the looping,then change the text to "stop" so that when the user clicks stops it stops at the current record? Go to youtube and look for multithreading videos,not sure how to help u on that one hope the rest helps. If this is useful please acknowledge

Answer 2

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
If Button1.Text = "Start" Then
If TextBox1.Text = "" Then
t1 = New Thread(AddressOf Me.PhoneThread)
t1.Start()
Button1.Text = "Stop"
Else
t1.Resume()
Button1.Text = "Stop"
End If
Else 'Click Stop
t1.Suspend()
Button1.Text = "Start"
If FirstWin.Text = "" Then
FirstWin.Text = TextBox1.Text
ElseIf SecondWin.Text = "" Then
SecondWin.Text = TextBox1.Text
ElseIf ThirdWin.Text = "" Then
ThirdWin.Text = TextBox1.Text
End If
End If
End Sub
Sub PhoneThread()
'Dim ThreadsArray As List(Of Threading.Thread) = New List(Of Threading.Thread)
Dim s As Integer
'MsgBox(DT.Rows.Count)
For s = 0 To DT.Rows.Count
If s = DT.Rows.Count Then
s = 0
Else
TextBox1.Text = DT.Rows(s)("Phone")
' ThreadsArray.Add(t1)
Thread.Sleep(19)
'TextBox1.Text = s.ToString()
Me.Refresh()
End If
Next
End Sub
Private Sub BtnStart_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnStart.Click
Me.Close()
End Sub

Answer 3

For something simple like this, System.Threading.Thread.Sleep(100) (to block the thread) followed by Application.DoEvents() (to process any button clicks) seems like it would do the trick.
For something more complicated, this approach will result in re-entrancy and difficult-to-reproduce bugs; in that case, you definitely need asynchronous programming.