[RESOLVED] Threading - Add textboxes to form in thread

[Jova]

Hi,

I would like your help again, please.

I'm just getting to grips with threading. I'm trying to add 20 textboxes to a form.

I have 2 forms. The first one (form1) has a button 'Load textboxes'. This will take me to the second form (form2) where in the OnLoad event, it will create 20 textboxes and place it on form2.

Each time, it adds a textbox to the form, it refreshes form2.

I used Threading for this. I wish I could use Backgroundworker. I'm using Visual Studio 2005 with Pocket PC 2003. The language is Visual Basic.

Here's my code.

This is in my module modPocketPhone

Imports System.Threading
Imports System.ComponentModel

Module modPocketPhone

    Private oThreadStart As ThreadStart
    Private oThread As Thread


    Public Sub loadMytextBox()
        oThreadStart = New ThreadStart(AddressOf populateScreen)

        oThread = New Thread(oThreadStart)

        oThread.Start()

        Dim myTextBox As New TextBox
        myTextBox.Text = "Test"
        myTextBox.Top = 0
        myTextBox.Left = 30
        myTextBox.BackColor = Color.Red
        myTextBox.ForeColor = Color.White
        Form2.Controls.Add(myTextBox)
        Form2.Refresh()

    End Sub


    Public Sub populateScreen()
        Dim myTextBox As TextBox = Nothing
        Dim iHeight As Integer = 50
        Dim iWidth As Integer = 200

        Dim iTop As Integer = 0
        Dim iOffset As Integer = 6

        Dim i As Integer = 1
        Dim j As Integer = 20

        For i = 1 To j
            myTextBox = New TextBox
            myTextBox.Text = "Box " & i
            myTextBox.Height = iHeight
            myTextBox.Width = iWidth
            myTextBox.BackColor = Color.Azure
            myTextBox.Visible = True
            myTextBox.Left = 0

            If i > 0 Then
                myTextBox.Top = iHeight + iTop + iOffset
            End If

            Try
                Form2.Controls.Add(myTextBox)
                Form2.Refresh()
                Debug.WriteLine("Control  " & i)
            Catch ex As Exception
                Debug.WriteLine(ex.Message)
            End Try

        Next
    End Sub

End Module

I ran the code. I didn't get any errors shown through my debugging.

The above code is executed when form2 is loaded once the button in form1 is pressed. Form2 loads and fires up the procedure 'loadMyTextbox'. When it does, it creates a thread calling up up the procedure 'populateScreen'. This is where it creates the textboxes onscreen.

This is my Form2 code.

Public Class Form2

    Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        loadMyTextBox()
    End Sub
End Class

I am doing this to create a questionnaire application. I noticed if I did not use Threading the process is quite intensive in loading controls to the screen. I can add a textbox to form2 without threading as you see in the lines followin 'oThread.Start'. I can see it on screen.

When the thread runs, I do not see any of my controls.

Can anyone please advise what I'm doing wrong?