Binding UI directly to API model

Question

Binding works without INotifyPropertyChanged, why?

Is it a bad practice to bind my UI to HTTP API model directly without creating a separate view model?

The only disadvantage is it won't implement INotifyPropertyChanged so UI won't update when you change the property from your code - but what if you don't need to update your property from your code?

This is my API response model:

public class EventResponseModel
{
    public int Id { get; set; }
    public string Subject { get; set; }
    public string Description { get; set; }
    public DateTime StartTime { get; set; }
    public DateTime EndTime { get; set; }
    public string ArgbColor { get; set; } // should bind to Brush
    public Location Location { get; set; }
    public IEnumerable<Person> Attendees { get; set; }
}

In the model above I have ArgbColor that need to be bound to Brush in XAML. I could probably create StringToBrushConverter : IValueConverter to make it work instead of creating a separate view model.

Is this always preferred to create a separate view model, map to it and then bind to it?

For editing, I would still have a separate VM and use a composition like:

public class EventVM 
{
    public EventResponseModel EditedEvent { get; set; }
    // available locations etc., commands for saving
}

"Is it a bad practice?" - no, not in my opinion. I would however recommend `public Color ArgbColor { get; set; }` and bind a SolidColorBrush's Color property. — Clemens, Jun 13 '19 at 09:14
`Color` needs a reference to `System.Media` or `PresentationCore`. This model is used on the server so `string` is the best type. — Konrad, Jun 13 '19 at 09:21
Does `ArgbColor` Value contains html clr codes ? like this( #1A85CD )? — Avinash Reddy, Jun 13 '19 at 10:46
@AvinashReddy yes, #AARRGGBB. It's not a problem to convert it using `BrushConverter` — Konrad, Jun 13 '19 at 10:53
Then why cant u just bind the string to color i mean `Background="{Binding ArgbColor }"` Like this. — Avinash Reddy, Jun 13 '19 at 10:57

score 1 · Accepted Answer · answered Jun 14 '19 at 12:57

Is it a bad practice to bind my UI to HTTP API model directly without creating a separate view model?

Not if you are and will be able to use the model class exactly as-is in your GUI application. Then there is no reason to create a view model wrapper just for the sake of it, since you basically have a dependency upon the API anyway.

Is this always preferred to create a separate view model, map to it and then bind to it?

No, not always. If you for example were to display a couple of hundreds or thousands of event responses in a grid of some kind, you don't want to invoke a converter for each item. In this case it would be better to wrap the model and bind directly to a UI friendly Brush property or similar. So it all depends on your requirements. But binding directly to domain objects isn't always a bad idea.

Binding UI directly to API model

1 Answers1