How to make a call using label

Hi

how can I make my label call by tapping that label with phone num as its text

    <Label Text="(02) 345 7854">
                <Label.GestureRecognizers>
                    <TapGestureRecognizer NumberOfTapsRequired="1" Tapped="TaptoCall"/>
                </Label.GestureRecognizers>
            </Label>

Then here is my back code

void TaptoCall(object sender, EventArgs args)
    {
        Device.OpenUri(new Uri("(02) 345 7854"));
    }

When I tap on that label my app crashes