Reading ComboBox Text or SelectedValue causes a Cross-thread error?

[Sorwen]

So for simplicity I have several TextBoxes, a couple NumericUpDowns, and a ComboBox on a form. After adding text and selecting a value for the ComboBox the user presses start and processing is done in a separate thread using System.Threading.Thread. However, for some reason only when reading from the ComboBox do I get a Cross-thread operation not valid. It is easy enough to fix since all I'm doing is reading the text, but I don't understand why it has to be done for a ComboBox and as yet no other control. I'm not setting the value or I could understand it having an issue. I've used ComboBoxes in the past and threading, but I don't remember having this problem before now. Maybe I've just avoided the combination up till now. So the question is I don't understand why?

-I hate Microsoft!
-Forever and always forward.
-My kingdom for a edit button!

 

[RonRepp]

What is version and code?

Ron Repp

If gray hair is a sign of wisdom, then I'm a genius.

My newest novel: Wooden Warriors

http://www.repproductions.net

 

[Sorwen]

VS2008

Public Class Form1
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim thrd As New System.Threading.Thread(AddressOf TestCB)
        thrd.Start()
    End Sub

    Private Sub TestCB()
        Dim tb As String
        Dim nud As Integer
        Dim cb As String

        tb = TextBox1.Text '<- Fine
        nud = NumericUpDown1.Value '<- Fine
        cb = ComboBox1.Text '<- Errors
    End Sub
End Class

Just seems really strange to me.

-I hate Microsoft!
-Forever and always forward.
-My kingdom for a edit button!

 

[Sorwen]

I thought I had mentioned it, but it looks like I didn't. SelectedText and SelectedValue cause the same problem.

-I hate Microsoft!
-Forever and always forward.
-My kingdom for a edit button!