Multi_Thread - How do I open frm2 in a 2nd thread?

[tgf-47]

Please correct me if I'm wrong, but multithreading will do the following:

I have a form frmInvMaint which loads about 800 000 records from my Pick database. I have a 2nd form frmLoading with a animated gif on it.

The reason for this is the application takes about 30seconds to return the selection from the DB. During that time, the application seems to be hanging (not responding). I added the frmLoading to show, before the selection executes. This way the user will see a animated loading gif on his screen, assuring him that the application is working in the background.

This is where the booboo hit the fan. My lame attempt on multi threading failed. The gif on frmLoading hangs, infact, the entire form hangs.

Will multithreading fix this if done properly? If yes, can anybody show me how to do this?

This is the code I used:

Public Shared Sub Main()
        Dim t As New Thread(AddressOf ThreadProc)
        t.Start()
        FrmLoading.Show()
    End Sub

[cicatrix]

Try this (Form1 and Form2 must be present in the project):

Imports System.ComponentModel
 
Public Class Form1
    Private bw As New BackgroundWorker With {
            .WorkerReportsProgress = True,
            .WorkerSupportsCancellation = True}
 
    Private frmProgress As New Form2
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Me.Load
        AddHandler bw.DoWork, AddressOf RunLongProcess
        AddHandler bw.ProgressChanged, AddressOf ProgressChanged
        bw.RunWorkerAsync()
    End Sub
 
    Private Sub RunLongProcess(ByVal sender As System.Object, ByVal e As DoWorkEventArgs)
        Dim progress As Integer
 
        For progress = 0 To 100
            System.Threading.Thread.Sleep(1000)
            bw.ReportProgress(progress)
        Next
    End Sub
 
    Private Sub ProgressChanged(ByVal sender As Object, ByVal e As ProgressChangedEventArgs)
        If Not frmProgress.Visible Then frmProgress.Show()
        ' Change to Progress bar or whatever - just a demonstration
        frmProgress.Text = e.ProgressPercentage.ToString()
    End Sub
End Class

[tgf-47]

Thanks. Now I have another issue with the thread.
In my thread sub, i populate a datatable

the datatable now has a rowcount of 97.
I can view the values if I do this:

MsgBox(dt_Final.Rows.Count)
MsgBox(dt_Final.Rows(1).Item(0))

but when I do this:

dgv.DataSource = dt_Final

No result... The dgv stays empty