Invoke inside backgroundworker

//funcation called inside DoWork of a backgroundworker
public bool ShowSupportLogon()
{
    bool erResult = false;
    System.Threading.Thread.Sleep(5000);//Time-consuming tasks
    //passing control to foreground/main thread to show the form
    this.Invoke((MethodInvoker)delegate()
    {
        DialogResult dr = er.ShowDialog();//er is the object of another form(global variable)
        if (dr == DialogResult.OK)
        {
            erResult = true;
        }
        else
        {
            erResult = false;
        }
    });
    System.Threading.Thread.Sleep(2000);//Time-consuming tasks
    return erResult;
}