CODEWITHSUNDEEP
wpfmvvm
Przetczak
Przetczak

Reputation: 131

Pass data from Service do ViewModel

Model:

class UserModel
{
    public string FirstName { get; set; }
}

Service:

class UserService
{
    private async Task<string> DirectoryEntry()
    {
        SearchResult rs = await Task.Run(() =>
        {
            DirectoryEntry de = new DirectoryEntry("xxx");
            DirectorySearcher ds = new DirectorySearcher(de)
            {
                Filter = "(&((&(objectCategory=Person)(objectClass=User)))(sAMAccountName=" + "xxx" + "))",
                SearchScope = SearchScope.Subtree
            };
            return ds.FindOne();
        });
        var value = (rs.GetDirectoryEntry().Properties["businessCategory"].Value ?? "BRAK").ToString();
        return value;
   }
}

ViewModel:

class UserViewModel : INotifyPropertyChanged
{
    UserModel user = new UserModel();

    public string FirstName
    {
        ??
    }

    public event PropertyChangedEventHandler PropertyChanged;

    protected void OnPropertyChange(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

So, how to pass value to ViewModel? I checked some examples but I can't achieve it between Service and VM. I totally don't know how to relate between them. Or maybe is it incorrect use of mvvm?

Upvotes: 0

Views: 654

Answers (1)

mm8
mm8

Reputation: 169420

Provided that your service method actually returns a value, the view model may do whatever it wants with this value like for example assigning it to a property of the UserModel or a property of itself assuming the types match.

In general, the view model has a reference to the service:

class UserViewModel : INotifyPropertyChanged
{
    readonly UserService service = new UserService();
    //call a method on the service in any method of the view model
}

In the above code, the view model has a strong reference to the implementation of the service. It's more common to inject the view model with an interface that the service implements:

class UserViewModel : INotifyPropertyChanged
{
    readonly IUserService _service;

    public UserViewModel(IUserService service) => _service = service;
}

You can then switch implementation at runtime. You may for example want to test your view model with a mock of the service, but use a "real" service implementation when running your actual application.

Upvotes: 1

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