Datagridview linked to datatable not getting updated - vb.net

Question

This is a part of simultaneous url download program that i'm trying to make. It has the url list saved in a datatable named tbl and it is bound to a datagridview named dgvUrls. Evrytime it encounters a dead url, it removes it from the datatable.
I've reproduced the error using the code below. The Button3_Click adds 100 rows to the datatable, makes it as the datasource for datagridview. The q() removes the rows one at a time by removing the 1st row. The prob is that the datagridview don't reflect the changes made in the datatable
Dim tbl = New DataTable
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
'Add 100 urls, for simplicity i'm adding only integers
tbl.Columns.Add("Urls")
For i = 1 To 100
tbl.Rows.Add(i)
Next
'bind to datagridview so that the end user can see the urls being download/removed from the list
dgvUrls.DataSource = tbl
'start multithread download , for simplicited (of this question) we have only one
Dim t As Thread = New Thread(AddressOf Download)
t.Start()
t.Join()
dgvUrls.Refresh()
End Sub
Private Sub download()
'for simplicity, the 1st 80 urls were dead!
For i = 1 To 80
'we remove the dead urls
tbl.Rows.RemoveAt(0)
Next

Answer 1

In general, it is a good thing to Refresh the DataGridView, mainly if you are performing the modifications from another thread; something like this:
Dim t As Thread = New Thread(AddressOf q)
t.Start()
t.Join() 'Waits for the other thread to complete, such that the next line is reached on the right moment
dgvUrls.Refresh()
I deleted Dim ts As ThreadStart = New ThreadStart(AddressOf q) because is not necessary. Also you don't need the Sleep and DoEvents:
Private Sub q()
For i = 1 To 98
tbl.Rows.RemoveAt(0)
Next
End Sub
As a proof of concept (to understand how all this works) is OK; but you should review various ideas in your logic before going further: removing so many rows from the DataSource can provoke problems (you would see that it triggers errors); ideally, (at least, I prefer it) you should modify the DataGridView directly (if possible) to avoid info-synchronisation problems; if you deal with multiple threads you would have to set up a "more proper structure" (the proposed t.Join() should be seen as a temporary fix to make this work).