cross thread operation not valid:Instantiating a form in BACKGROUNDWORKER & getting error when trying to use it in other form

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one of my form takes hell lot of time to load, reason being the class i am using is intantiated before the form could load.
now for the time the form takes to load, i display a loading image(on a form) using background worker.
Now after the original form is intatiated in the backgroundworker, i am trying to show the form in a different function where i assign it to an MDIPArent form.
here i get the error 'cross thread operation not valid: control 'form' accessed from a thread other than the thread it wasa created on'.
kindly help as evrything else is working fine xcept dis..
thanking you in anticipation.

Posted 20-May-13 23:35pm

aryan_85

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E.F. Nijboer 21-May-13 5:39am

Have you googled it? This is a very common beginners error. You need to invoke the UI thread if you want to update UI elements.

aryan_85 21-May-13 5:41am

of corse i did...but in vain.
Do u knw d way to access UI elements after dey r created/instantiated in backgroundworker??
:-(

aryan_85 21-May-13 6:42am

thanx Nijboer...
found something that worked perfectly..
ur comment helped me to guide/lead to the real cause of the error
:-)

E.F. Nijboer 21-May-13 8:59am

Nice to help you find it :-)

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aryan_85 · Accepted Answer · 2013-05-21T00:50:00

To access the controls that r created in the background-worker..use the invoke method of the controls-

below code is in DO_WORK() method of backgroundworker

'form_name is a string argument passed to RunWorkerAsync method
dim frm as form = activator.createinstance(form_name,form)

'here "me" is d MDIPARENT of d form "frm" which will be assgned in a method below

Me.Invoke(New Action(Function()
ShowForm(frm) 'ShowForm is a method that displays the form "frm" by assigning a MDIParent to it
End Function))

it worked perfectly fine