Question

I’m implementing a custom Button class that inherits from System.Windows.Forms.Button, I do a custom paint of the button, including the button text. I want to support accelerator keys (hotkeys) for my buttons.

Little explanation: In an standard button, when the ALT key is pressed, the accelerator character is underlined:

  button.Text = "&Capture screen";

When you press ALT key in the application, the button underlines the “C” charater.

So, when I paint the button text, I need to know when accelerator underlines are active or not, to draw my text underlined or not.

• How could I subscribe to receive accelerator messages?
• Is an event?
• Is a WND_PROC message?
• Is there managed code to get it?

Thanks in advance.

Answer 1

If you want to detect whether the Alt key was pressed inside the Paint event handler of the button, you have check the ModifierKeys property of the form:

    private void button1_Paint(object sender, PaintEventArgs e)
    {
        if (ModifierKeys == Keys.Alt)
            button1.Text = "Alt Pressed - " + button1.Text;
    }