public static ToolStripTextBox onKeyPress(this ToolStripTextBox toolStripTextBox, Keys onlyFireOnKey, Action <String> callback) { toolStripTextBox.KeyDown += (sender, e) => { if (e.KeyData == onlyFireOnKey) { callback(toolStripTextBox.get_Text()); e.SuppressKeyPress = true; } }; return(toolStripTextBox); }