Invokereqired to checkbox

I just need to create a function to checkbox that will return the current value of checkbox.

I wrote :

private void Checkbox_check()
        {
            if (checkBox1.InvokeRequired)
                return (int)checkBox1.Invoke(new Func<int>(checked));
            else
                return checkBox1.Checked; // bad here i know

        }

What is bad here, can someone just write correctly this function? I need Invoke because can't use in another Thread without invoke. I just search a forum and web about help but can't find solution anywhere.