Awesome
EntityViews
This project generates ViewModels based on the models of the application using source generators.
The generated ViewModels implement INotifyPropertyChanged
and re-use any DataAnnotations
attribute to simplify the client-side validation by reducing boilerplate code.
Example
Imagine we have a WebApi to build a TodoList (the next class is also a valid class for EntityFramework):
public class TodoItem
{
public int Id { get; set; }
[Required]
[MaxLength(50)]
public string Name { get; set; } = string.Empty;
public bool IsComplete { get; set; }
}
Now we need to build a client so the user can populate the ToDo list, this projects uses source generators to build a ViewModel based on the previous object, the generated code
will use the Required
and MaxLength
attributes to validate the object and quickly build the user interface.
This project generates a lot of boring, repeating, and neccessary code for us. the auto-generated view model will look like:
public partial class TodoItemViewModel : INotifyPropertyChanged
{
private Dictionary<string, string> _validationErrors = [];
// ...
private string _name = string.Empty;
[Required]
[MaxLength(50)]
public string Name { get => _name; set => SetProperty(ref _name, value, nameof(Name)); }
public string NameError => GetError("Name");
public bool NameHasError => NameError.Length > 0;
// ...
public event PropertyChangedEventHandler? PropertyChanged;
/// <summary>
/// Validates the view model and returns true if there are no validation errors.
/// </summary>
public bool IsValid()
{
// ...
}
// ...
}
Finally we can quickily validate user interfaces in a client app:
In this case, it is a Maui client defined with the next XAML:
<Label Text="Name" />
<Entry Text="{Binding Name}">
<Entry.Triggers>
<DataTrigger TargetType="Entry" Binding="{Binding NameHasError}" Value="True">
<Setter Property="BackgroundColor" Value="#50ff0000"/>
</DataTrigger>
</Entry.Triggers>
</Entry>
<Label Text="{Binding NameError}" TextColor="Red"/>
<Button Text="Save" Command="{Binding SaveCommand}"/>