Xamarin MVVM pass object properties - xamarin

Question

So I'm pretty new to the whole MVVM thing. I pretty much understand the basics of it. I have an example that's working just find as it is but I'm trying to change it into the MVVM style. Im just trying out different examples so I can learn.
(LoginPage.xaml)
On the XAML side I have a label with a tap gesture. pretty single
<!-- Existing Tab -->
<Label x:Name="labelName"
Grid.Column="0"
Style="{StaticResource CenteredTextTitle}"
Text="Log In">
<Label.GestureRecognizers>
<TapGestureRecognizer Tapped="SelectorOption_Tapped" />
</Label.GestureRecognizers>
</Label>
LoginPage.xaml.cs page
I can access it by creating a tapped function.
private async void SelectorOption_Tapped(object sender, EventArgs e)
{
if (!(sender is Xamarin.Forms.View view)) return;
int index = Grid.GetColumn(view);
...
}
now im trying to change that into MVVM..
So the XAML stays the same
on the ViewModel page
loginpageviewmodel.cs page
public LoginPageViewModel()
{
btnSubmit_Clicked = new Command(SubmitClicked);
}
public ICommand btnSubmit_Clicked { get; set; }
private void SubmitClicked(object parameter)
{
if (!(parameter is Xamarin.Forms.View view)) return;
var index = Grid.GetColumn(view);
}
i can run the function submitclicked. But i cant pass on the parameter. Its always null.
i want to get the column from the grid that i have based on what the user selects. it works fine the original way but if i try to change it to MVVM i cant pass the view form to get the getcolumn..
is there anyway i can pass that.?

Answer 1

The parameter comes from the CommandParameter you set in the xaml:
<StackLayout>
<!-- Place new controls here -->
<Label x:Name="myLabel" HorizontalOptions="CenterAndExpand" VerticalOptions="CenterAndExpand" Text="Log In">
<Label.GestureRecognizers>
<TapGestureRecognizer Command="{Binding btnSubmit_Clicked}" CommandParameter="{x:Reference myLabel}"/>
</Label.GestureRecognizers>
</Label>
</StackLayout>
In code behind:
public partial class MainPage : ContentPage
{
public MainPage()
{
InitializeComponent();
BindingContext = new LoginPageViewModel();
}
}
public class LoginPageViewModel
{
public LoginPageViewModel()
{
btnSubmit_Clicked = new Command(SubmitClicked);
}
public ICommand btnSubmit_Clicked { get; set; }
private void SubmitClicked(object parameter)
{
if (!(parameter is Xamarin.Forms.View view)) return;
Console.WriteLine(parameter);
}
}