CheckButton.CheckedChanged Event

public event EventHandler CheckedChanged

event Public CheckedChanged As EventHandler

checkButton1.CheckedChanged += (s, ea) => {
    CheckButton btn = s as CheckButton;
    if (btn.Checked) {
        //... 
    }
};

AddHandler CheckButton1.CheckedChanged, Sub(s, ea)
    Dim btn As CheckButton = TryCast(s, CheckButton)
    If btn.Checked=True Then 
        '... 
    End If 
End Sub