InvokeRequired in wpf [duplicate]

In WPF, the Invoke method is on the dispatcher, so you need to call Dispatcher.Invoke instead of Invoke. Also, there is no InvokeRequired property, but the dispatcher has a CheckAccess method (for some reason, it’s hidden in intellisense). So your code should be:

delegate void ParametrizedMethodInvoker5(int arg);
void log_left_accs(int arg)
{
    if (!Dispatcher.CheckAccess()) // CheckAccess returns true if you're on the dispatcher thread
    {
        Dispatcher.Invoke(new ParametrizedMethodInvoker5(log_left_accs), arg);
        return;
    }
    label2.Text= arg.ToString();
}