Using C# how can I return the value of a toggle Switch from xaml-CodePudding

I have two xaml toggles in separate files that I want to update simultaneously (if one is switched on the other should be too (and vice versa). My first switch in xaml is:

<Switch Grid.Column="1" x:Name="toggleSwitch1" IsToggled="true" Toggled="OnToggled"/> with the method

 void OnToggled(object sender, ToggledEventArgs e)
    {
        //updateConsentValueForCategory();
        if (toggleSwitch1.IsToggled)
        {
            Console.WriteLine("Toggled on");
        }
        else
        {
            Console.WriteLine("Toggled off");
        }
    }

Converting OnToggled() to a return type gives me an error for toggleSwitch1 saying an object reference is required because it is non-static. How can I pull the toggle value and update another xaml file in sync?

CodePudding user response：

the sender object contains the source of event, here the Switch

 void OnToggled(object sender, ToggledEventArgs e)
    {
        //updateConsentValueForCategory();
        var switch = (Switch)sender;
        if (switch.IsToggled)
        {
            Console.WriteLine("Toggled on");
        }
        else
        {
            Console.WriteLine("Toggled off");
        }
    }

CodePudding user response：

Using C# how can I return the value of a toggle Switch from xaml

You can use several methods to achieve this .

1.use event Toggled of Switch as you mentioned.

You can refer to the following code:

private void OnToggled(object sender, ToggledEventArgs e)
{
    Switch mySwitch1 = (Switch)sender;
    if (mySwitch1.IsToggled)
    {
        Console.WriteLine("Toggled on" );
    }
    else
    {
        Console.WriteLine("Toggled off");
    }
}

2.Another method is to use the binding way.

Just create a ViewModel for the current page(e.g.TestPage1) and create a field (e.g. SwithOne) for property IsToggled of Switch .

Please refer to the following code :

Create a ViewModel class(e.g. MyViewModel.cs) and create field SwithOne .Make the ViewModel implement interface INotifyPropertyChanged.

 public class MyViewModel: INotifyPropertyChanged
{
    private bool swithOne;
    public bool SwithOne
    {
        set
        {
            if (swithOne != value)
            {
                swithOne = value;
                OnPropertyChanged("SwithOne");
            }
        }
        get
        {
            return swithOne;
        }
    }


    public MyViewModel()
    {
        SwithOne = true; // assign a value for `SwithOne `
    }

    bool SetProperty<T>(ref T storage, T value, [CallerMemberName] string propertyName = null)
    {
        if (Object.Equals(storage, value))
            return false;

        storage = value;
        OnPropertyChanged(propertyName);
        return true;
    }

    protected void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }

    public event PropertyChangedEventHandler PropertyChanged;

}

TestPage1.xaml.cs.

public partial class TestPage1 : ContentPage
{
     MyViewModel myViewModel;

    public TestPage1()
    {
        InitializeComponent();

        myViewModel = new MyViewModel();
        BindingContext = myViewModel;
    }

    //private void OnToggled(object sender, ToggledEventArgs e)
    //{
    //    Switch mySwitch1 = (Switch)sender;
    //    if (mySwitch1.IsToggled)
    //    {
    //        Console.WriteLine("Toggled on");

    //    }
    //    else
    //    {
    //        Console.WriteLine("Toggled off");

    //    }
    //} 

}

TestPage1.xaml

        <Switch x:Name="toggleSwitch1" IsToggled="{Binding SwithOne}"   HorizontalOptions="Center">
        </Switch>
        <Button  Text="navigate"  Clicked="Button_Clicked"/>