只有在xamarin.forms中填写表单后才会激活的按钮

<Button Text="提交" IsEnabled="False" Command="{Binding SubmitCommand}" />

public class MyViewModel : INotifyPropertyChanged
{
    private string name;
    private string email;

    public string Name
    {
        get { return name; }
        set
        {
            if (name != value)
            {
                name = value;
                OnPropertyChanged(nameof(Name));
                ((Command)SubmitCommand).ChangeCanExecute();
            }
        }
    }

    public string Email
    {
        get { return email; }
        set
        {
            if (email != value)
            {
                email = value;
                OnPropertyChanged(nameof(Email));
                ((Command)SubmitCommand).ChangeCanExecute();
            }
        }
    }

    public ICommand SubmitCommand { get; }

    public MyViewModel()
    {
        SubmitCommand = new Command(Submit, CanSubmit);
    }

    private bool CanSubmit()
    {
        // 判断表单是否填写完整
        return !string.IsNullOrEmpty(Name) && !string.IsNullOrEmpty(Email);
    }

    private void Submit()
    {
        // 处理提交逻辑
    }

    // 实现INotifyPropertyChanged接口的代码省略...
}