Xamarin Label Click change Checkbox State Only Xaml

Question

I am trying to change the state of a Checkbox in Xamairn.

My Xaml Code

<StackLayout Orientation="Horizontal">
    <CheckBox VerticalOptions="Start"
        IsChecked="{Binding IsChecked,Mode=TwoWay}">
        <CheckBox.Margin>
            <OnPlatform x:TypeArguments="Thickness">
                <On Platform="iOS" Value="0,-10,0,0" />
                <On Platform="Android, WinPhone, Windows" Value="0,-5,0,0" />
            </OnPlatform>
        </CheckBox.Margin>
    </CheckBox>
    <Label VerticalTextAlignment="Center" VerticalOptions="Start"
        Text="{Binding Text}">
        <Label.GestureRecognizers>
            <TapGestureRecognizer>

            </TapGestureRecognizer>
        </Label.GestureRecognizers>
    </Label>
</StackLayout>

I know I have done this before but I forgot.

I have to add a setter or something in the TapGestureRecognizer to make the Checkbox IsChecked=True and IsChecked=False when its True

Answer 1

To do it in an MVVM way what you are looking for is the Command.

In your ViewModel add the command:

public ICommand ChangeStateCommand { get; set; }

and in the Constructor initialize it:

ChangeStateCommand = new Command(() => IsChecked = !IsChecked);

Then you will need to bind it with the TapGestureRecognizer of your Label.

<StackLayout Orientation="Horizontal" VerticalOptions="CenterAndExpand">
    <CheckBox VerticalOptions="Start"
              IsChecked="{Binding IsChecked,Mode=TwoWay}">
        <CheckBox.Margin>
            <OnPlatform x:TypeArguments="Thickness">
                <On Platform="iOS" Value="0,-10,0,0" />
                <On Platform="Android, WinPhone, Windows" Value="0,-5,0,0" />
            </OnPlatform>
        </CheckBox.Margin>
    </CheckBox>
    <Label VerticalTextAlignment="Center" VerticalOptions="Start"
                                           Text="{Binding Text}" >
        <Label.GestureRecognizers>
            <TapGestureRecognizer Command="{Binding ChangeStateCommand}" />
        </Label.GestureRecognizers>
    </Label>
</StackLayout>

Hope this helps.-

Answer 2

Give a name to checkBox and a tapEvent to label, then change the isChecked property in code behind:

<StackLayout Orientation="Horizontal">
    <CheckBox VerticalOptions="Start" x:Name="myCheckBox"
    IsChecked="{Binding IsChecked,Mode=TwoWay}">
        <CheckBox.Margin>
            <OnPlatform x:TypeArguments="Thickness">
                <On Platform="iOS" Value="0,-10,0,0" />
                <On Platform="Android, WinPhone, Windows" Value="0,-5,0,0" />
            </OnPlatform>
        </CheckBox.Margin>
    </CheckBox>
    <Label VerticalTextAlignment="Center" VerticalOptions="Start"
    Text="{Binding Text}">
        <Label.GestureRecognizers>
            <TapGestureRecognizer Tapped="TapGestureRecognizer_Tapped">
            </TapGestureRecognizer>
        </Label.GestureRecognizers>
    </Label>
</StackLayout>

And in code behind:

private void TapGestureRecognizer_Tapped(object sender, EventArgs e)
{
    myCheckBox.IsChecked = !myCheckBox.IsChecked;

    //or change the IsChecked property in ViewModel
    //myViewModel.IsChecked = !myViewModel.IsChecked;
}