Xamarin Forms - How to create Commands with MVVM

Question

When creating a command (e.g. for a button), I would do so like this:

In the ViewModel class

public Command ConfirmLogoutCommand { get; }


    public LogoutPageViewModel()
    {
        ConfirmLogoutCommand = new Command(async () => await ExecuteConfirmLogoutCommand());
    }

    private async Task ExecuteConfirmLogoutCommand()
    {
        await Shell.Current.GoToAsync($"//{nameof(LoginPage)}");
    }

Which seems to work OK, but I get a warning on the "async" part that says "Avoid using 'async' lambda when delegate type returns 'void'"

How do I alter the basic code above to solve that issue?

Answer 1

Hello,​

Welcome to our Microsoft Q&A platform!

Please change the code like following format.

   public Command ConfirmLogoutCommand { get; }  
        public LogoutPageViewModel()  
        {  
                ConfirmLogoutCommand = new Command( ExecuteConfirmLogoutCommand);  
        }  
     
              
     
        private async void ExecuteConfirmLogoutCommand()  
           {  
               await Shell.Current.GoToAsync($"//{nameof(LoginPage)}");  
           }  

Best Regards,

Leon Lu

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