Form is disposed when the thread completes

I know the problem but can't find the solution. Please help

I have 2 forms in my application (Form1 and Form2, Form1 is the startup form). I am connecting to the database in a new thread (In the FormLoad event of Form1, please see the code below) . If the connection to database on line# 4 fails i show Form2 (Which is basically a DB settings Form) but the form is disposed when the thread completes . How can make Form2 stay on the screen. Please see the code below

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1. Public Class Form1
2.     Private Sub connectDB()
3.         Try
4.             'DB connection code goes here ...
5.  
6.         Catch ex As Exception
7.             Dim f As New Form2
8.             f.Show()
9.         End Try
10.     End Sub
11.     Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
12.         Dim t As New Threading.Thread(AddressOf connectDB)
13.         t.IsBackground = False
14.         t.Start()
15.     End Sub
16. End Class
17.  

but im pretty sure it will freeze unless you set the background property to true, and im not sure if you can access pre-dimmed variables on the main thread, from a child thread...well try it and let me know...

joedeene

The problem is that you are creating your Form2 instance in a different thread, so it is natural that it will be closed as soon as the thread has ended.

Whenever you use multiple threads in .Net be careful to invoke all Gui related commands from a Gui thread. Search help for InvokeRequired property, and BeginInvoke() method. You should end up with something like this:

Call the ShowFormOnMainThread() method from your background thread to invoke it on a main thread.

This is a very common issue when working with .NET Gui from different threads, so you should get used to it. :)

Thanks vekipeki for your help. It took me a day to understand this little function but this right way to deal with multiple threads