How does this simple function hang up?

[eBob.com]

The dirt simple function below hangs up the thread it is executing on.

Private Function PurifyTelnum(ByVal telnum As String) As String

' drop trailing " "

Dim nbspIndex As Integer = telnum.Length - 5 ' offset to " "
if it's at the end of the string
If telnum.Substring(nbspIndex, 6) = " " Then
Return telnum.Substring(0, telnum.Length - 6)
End If

' drop imbedded "&nbsp;<br>" and then get rid of redundant blanks

Return CleanUpIdiomas(telnum.Replace("&nbsp;<br>", " "))

Return telnum
End Function

In single-stepping thru the code the last statement highlighted is
If telnum.Substring(nbspIndex, 6) = "&nbsp;" Then
I see no indication that it gets to the Return statement below it.

When I do a "Break All" and try to look at the thread I get a pop-up saying
that there is no source code corresponding to the location (but it does not
say what source code it is looking for).

TaskManager indicates that the problem is not a CPU loop.

This is driving me nuts! I'll be grateful if one of you guys spots the
problem.

Thanks, Bob

[eBob.com]

I put the code below into a separate and trivial application and discovered
right off that the PurifyTelnum function has at least one dumb error -
nbspIndex can be less than 0. This causes a pop-up when the error occurs in
the trivial application. But in my "real" application where this code is
running in its own thread there is no pop-up. Is this because I've done
something wrong in the way I do the multi-threading? Or is it just the way
it is? I hope it's some dumb mistake on my part because it was a real pain
to find the source of the problem without the error pop-up.

Thanks, Bob
"eBob.com" <eB******@totallybogus.comwrote in message
news:%2****************@TK2MSFTNGP04.phx.gbl...

The dirt simple function below hangs up the thread it is executing on.

Private Function PurifyTelnum(ByVal telnum As String) As String

' drop trailing "&nbsp;"

Dim nbspIndex As Integer = telnum.Length - 5 ' offset to "&nbsp;"
if it's at the end of the string
If telnum.Substring(nbspIndex, 6) = "&nbsp;" Then
Return telnum.Substring(0, telnum.Length - 6)
End If

' drop imbedded "&nbsp;<br>" and then get rid of redundant blanks

Return CleanUpIdiomas(telnum.Replace("&nbsp;<br>", " "))

Return telnum
End Function

In single-stepping thru the code the last statement highlighted is
If telnum.Substring(nbspIndex, 6) = "&nbsp;" Then
I see no indication that it gets to the Return statement below it.

When I do a "Break All" and try to look at the thread I get a pop-up
saying that there is no source code corresponding to the location (but it
does not say what source code it is looking for).

TaskManager indicates that the problem is not a CPU loop.

This is driving me nuts! I'll be grateful if one of you guys spots the
problem.

Thanks, Bob