Problem with checkbox check n uncheck

private void OnSpaceStatusChecked ( object sender, EventArgsEndpointStatus e )
{
 Thread newThread = new Thread(DoYourBackgroundWork);
 newThread.IsBackground = true;
 // You can pass a parameter here, which can be retrieved from the obj parameter in the DoYourBackgroundWork  function.
 newThread.Start(param); 
}

private void DoYourBackgroundWork(object obj)
{
 //Do some backgroundwork. 
 //...
 
 //MethodInvoker should be used only if the method you want to call doesn't have any parameters.
 //If you require the use of parameters, create a delegate for it and call its invoke method.
 this.Invoke(new MethodInvoker(UpdateTheUIs));
}

private void UpdateTheUIs()
{
 //Update your UI controls here.
}

// Please declare this delegate before your class definition, ie. it sits on top of class declaration.
public delegate void UpdateUI(object params);
// Create a reference as a class field. To be declared after the class defenition
UpdateUI update;

private void OnSpaceStatusChecked ( object sender, EventArgsEndpointStatus e )
{
 //Point your delegate to the function
 update = UpdateTheUIs;
 Thread newThread = new Thread(DoYourBackgroundWork);
 newThread.IsBackground = true;
 // You can pass a parameter here, which can be retrieved from the obj parameter in the DoYourBackgroundWork  function.
 newThread.Start(param);
}

private void DoYourBackgroundWork(object obj)
{
 //Do some backgroundwork. 
 //...
 //Pass the delegate object together with the parameter so that it can call the UpdateTheUIs function without encountering any cross-thread exception. Use the obj parameter with values that will be required to update your UI.
 this.Dispatcher.Invoke(update , obj);
}

private void UpdateTheUIs(object param)
{
 // From param you will receive "obj" called from the above invoke.
 // Use it accordingly
 //Update your UI controls here.
}