How to make application transparent on button click?

Question

C++ / C#

I have an application I want to have on button click (for example it's 'Home' button). The application became transparent. And vice versa.

Answer 1

The form has events that catch keystrokes.
These are KeyPress, KeyDown and KeyUp.
In order for the key interception to work at the level of the form itself, you must specify in its constructor: Then you can do this:

private void Form1_KeyUp(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Home)
            {
                this.Opacity = 0.9;
            }
        }

Opacity indicates the percentage of the form's transparency.