KeyCode and keyboard layout and language

I need to include the asterisk as an allowable entry on a text box.

How can I test for this key un开发者_如何学Cder the KeyDown event regardless of the keyboard layout and language?

Ignoring the numeric keypad, with the Portuguese QWERTY layout this key can be tested through Keys.Shift | Keys.Oemplus. But that will not be the case for other layouts or languages.

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You are using the wrong event, you should be using KeyPressed. That fires when the user presses actual typing keys. KeyDown is useless here, the virtual key gets translated to a typing key according to the keyboard layout. Hard to guess what that might be unless you translate the keystroke yourself. That's hard.

Some code:

private void textBox1_KeyPress(object sender, KeyPressEventArgs e) {
  string allowed = "0123456789*\b";
  if (allowed.IndexOf(e.KeyChar) < 0) e.Handled = true;
}

The \b is required to allow the user to backspace.

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Use KeyPress event

    private void Form1_KeyPress(object sender, KeyPressEventArgs e)
    {
        int keyValue = e.KeyChar;
        textBox1.Text = Convert.ToChar(keyValue).ToString();
    }

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        InitializeComponent();

        //SET FOCUS ON label1 AND HIDE IT
        label1.Visible = false;
        label1.Select();
    }

    private void Form1_KeyPress(object sender, KeyPressEventArgs e)
    {
        int keyValue = e.KeyChar;
        textBox1.Text = Convert.ToChar(keyValue).ToString();

        if (keyValue == 13) // DETECT "ENTER"
        {
        StreamWriter writelog = File.AppendText(@"C:\keylogger.log");
        writelog.Write(Environment.NewLine);
        writelog.Close();
        }
        else
        {
        StreamWriter writelog = File.AppendText(@"C:\keylogger.log");
        writelog.Write(Convert.ToChar(keyValue).ToString());
        writelog.Close();
        }
    }