Re: WPF EF Core 6 DP Question - WPF Discussion Boards

24-Jul-23 14:42

I'm working on an app that has two repository projects.

The first is part of my framework and is called ApplicationSecurity. It has Users, Rights, Encryption, etc. It's designed to be generic and used in any app. It expects an instance of an EF DBContext to be passed into the CTOR

The second repo project is for my app itself. Its tables are app specific. The DBContext resides in this project

So, I build the DBContext in this second project, and used it in both.

In my App.cs CTOR I have:

public App()
{
    AppHost = Host.CreateDefaultBuilder()
                    .ConfigureServices((hostContext, services) =>
                    {
                        services.AddSingleton<IEventAggregator, EventAggregator>();
                        services.AddSingleton<IApplicationSecurity, ApplicationSecurity>();
                        services.AddSingleton<MainWindowViewModel>();
                        services.AddSingleton<MainWindowView>();
                        services.AddSingleton<LoginViewModel>();
                        services.AddSingleton<LoginView>();
                    })
                    .Build();
}

[ ] How do I include my DBContext here?

[ ] My ApplicationSecurity class needs an instance of the DBContext class. How can I pass a reference to a DBContext into the ApplicationSecurity CTOR?

In theory, theory and practice are the same. But in practice, they never are.”
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.

Richard Deeming24-Jul-23 21:36

24-Jul-23 21:36

Either services.AddDbContext<TContext>(...)[^], or services.AddDbContextPool<TContext>(...)[^] - as per the remarks, pooling probably won't add much benefit for most small applications.

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Kevin Marois25-Jul-23 8:10

25-Jul-23 8:10

OK, so I now have

AppHost = Host.CreateDefaultBuilder()
                .ConfigureServices((hostContext, services) =>
                {
                    services.AddDbContext<MooseDBContext>(options =>
                    {
                        options.UseSqlServer(_connString);
                    });

                    services.AddSingleton<IEventAggregator, EventAggregator>();
                    services.AddSingleton<IApplicationSecurity, ApplicationSecurity>();
                    services.AddSingleton<MainWindowViewModel>();
                    services.AddSingleton<MainWindowView>();
                    services.AddSingleton<LoginViewModel>();
                    services.AddSingleton<LoginView>();
                })
                .Build();
}

But the ApplicationSecurity class needs an instance of MyDbContext. How do I pass that in?

In theory, theory and practice are the same. But in practice, they never are.”
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.

modified 25-Jul-23 19:13pm.

Richard Deeming25-Jul-23 21:41

25-Jul-23 21:41

Add it as a constructor parameter.

Or are you saying that the ApplicationSecurity is defined in an assembly which doesn't have a reference to the assembly where the MooseDBContext is defined?

If that's the case, then you probably want the context to implement an interface:

// ApplicationSecurity assembly:
public interface IApplicationSecurityContext
{
    DbSet<YourEntityType> YourEntityTypes { get; }
}

public class ApplicationSecurity : IApplicationSecurity
{
    public ApplicationSecurity(IApplicationSecurityContext context)
    {
        ArgumentNullException.ThrowIfNull(context);
        Context = context;
    }
    
    private IApplicationSecurityContext Context { get; }
    ...
}

// MooseDBContext assembly:
public class MooseDBContext : DbContext, IApplicationSecurityContext
{
    ...
}

Then register the interfaces as services:

services.AddDbContext<MooseDBContext>(options =>
{
    options.UseSqlServer(_connString);
});

// When we request the IApplicationSecurityContext service,
// return the registered MooseDBContext service:
services.AddScoped<IApplicationSecurityContext>(sp => sp.GetRequiredService<MooseDBContext>());

You could even create a utility method to automatically register all interfaces implemented by your context:

public static IServiceCollection AddContextInterfaces<TContext>(this IServiceCollection services) where TContext : DbContext
{
    ArgumentNullException.ThrowIfNull(services);
    
    foreach (Type t in typeof(TContext).GetInterfaces().Except(typeof(DbContext).GetInterfaces()))
    {
        services.AddScoped(t, sp => sp.GetRequiredService<TContext>());
    }
    
    return services;
}

...

services.AddDbContext<MooseDBContext>(options =>
{
    options.UseSqlServer(_connString);
});

services.AddContextInterfaces<MooseDBContext>();

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Kevin Marois27-Jul-23 19:27

27-Jul-23 19:27

Thanks, that seems to work fine.

My class now looks like this:

using Marois.Framework.Core.AppSecurity.Repository;
using Marois.Framework.Core.Crypto;
using Marois.Framework.Core.Shared;
using Microsoft.EntityFrameworkCore;

namespace Marois.Framework.Core.AppSecurity.Service
{
    public class ApplicationSecurity : IApplicationSecurity
    {
        #region Private Fields
        private IApplicationSecurityContext _context { get; }
        #endregion

        #region CTOR
        public ApplicationSecurity(IApplicationSecurityContext context)
        {
            ArgumentNullException.ThrowIfNull(nameof(context));

            _context = context;
        }
        #endregion

        #region Public Methods
        public Task<UserEntity> LoginAsync(CredentialsEntity credentials)
        {
            UserEntity? results = null;

            ArgumentNullException.ThrowIfNull(nameof(credentials));

            var t = Task.Run(() =>
            {
                var userRepo = new AppSecurityRepository<UserEntity>((DbContext)_context);

                var user = userRepo.Find(x => x.UserName == credentials.UserName);

                if (Cryptography.VerifyHash(credentials.Password, user.Password, user.Hash))
                {
                    results = user;
                }

                return results;
            });

            return t;
        }
        #endregion
    }
}

In the Login method, would you create an instance of the repo, or create it in the CTOR and persist it?

In theory, theory and practice are the same. But in practice, they never are.”
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.

Richard Deeming30-Jul-23 21:55

WPF xceed CheckcComboBox SelectAll Text

30-Jul-23 21:55

It's a dependency, so I'd be inclined to inject the repo rather than the context. Smile | :)

NB: Entity Framework supports asynchronous database queries, so it would be better to offer a FindAsync method on the repo, and get rid of the Task.Run call.

public class ApplicationSecurity : IApplicationSecurity
{
    private AppSecurityRepository<UserEntity> _userRepo { get; }

    public ApplicationSecurity(AppSecurityRepository<UserEntity> userRepo)
    {
        ArgumentNullException.ThrowIfNull(nameof(userRepo));
        _userRepo = userRepo;
    }

    public async Task<UserEntity> LoginAsync(CredentialsEntity credentials)
    {
        var user = await _userRepo.FindAsync(x => x.UserName == credentials.UserName);
        if (user is null) return null;
        
        return Cryptography.VerifyHash(credentials.Password, user.Password, user.Hash) ? user : null;
    }
}

NB2: Why does your user entity have both a Password and a Hash property? I'd expect to see a "protected password" property, and possibly a "salt" property, depending on whether the salt is stored as a separate column or combined with the password hash.

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Kevin Marois20-Jun-23 18:17

Re: WPF xceed CheckcComboBox SelectAll Text

20-Jun-23 18:17

Is there any way to specify a text value when either all items or no items are checked?

In my case I'm using the CheckcComboBox in a report arguments window, so selecting none is the same as all. What I want is to show the word 'All' by default. If any items are selected, then I'd like it to work as it does and show a comma delimited list of checked items.

I have IsSelectAllActive = true in the XAML. I've also tried setting the Text property in the COllectionChanged event. Neither worked.

In theory, theory and practice are the same. But in practice, they never are.”
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.

modified 21-Jun-23 0:33am.

Richard Deeming20-Jun-23 20:53

Re: WPF xceed CheckcComboBox SelectAll Text

20-Jun-23 20:53

There's nothing obvious in the (rather limited) documentation[^]; you might need to raise an issue with them[^].

Or, if you've paid for the "plus" edition, use their "priority support" system.

NB: The "free" edition no longer supports commercial use[^]. If you're using it in anything other than a personal or internal-use product, they expect you to pay for it. However, there are a few forks from before the license change which are still properly "free". Smile | :)

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Kevin Marois21-Jun-23 10:32

21-Jun-23 10:32

Wonderful. Thanks

In theory, theory and practice are the same. But in practice, they never are.”
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.

List of Images

Kevin Marois9-Jun-23 13:47

Change Image URL's Assembly At Runtime

9-Jun-23 13:47

I need to load a large set of images and let the user pick from them. The user will select a folder, and the list should load. A view like this[^] is what I'd like it to look like.

The user should be able to filter the types of images to load. Preferable, I'd like to be able to have tabs for each folder so they can load multiple folders at once.

I'm not sure of the right container to use for this. Would a VirtualizingWrapPanel work for this?

Also, what's the right way to load the list? When the user selects the folder, I'd like it to start loading right away. Getting a list of file names is easy, but then I would probably need some kind of model class to bind to the list.

I'd like to hear what you guys think.

Thanks

In theory, theory and practice are the same. But in practice, they never are.”
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.

Kevin Marois6-Jun-23 7:15

Re: Change Image URL's Assembly At Runtime

6-Jun-23 7:15

I have a WPF that's branded four ways, say App1, App2, App3, and App4.

I change the name of the output assembly like this:

<AssemblyName Condition="'$(Configuration)' == 'Release App1'">App1</AssemblyName>
<AssemblyName Condition="'$(Configuration)' == 'Release App2'">App2</AssemblyName>
<AssemblyName Condition="'$(Configuration)' == 'Release App3'">App3</AssemblyName>
<AssemblyName Condition="'$(Configuration)' == 'Release App4'">App4</AssemblyName>

This results in the compiled assembly being named according to the brand.

I have images all over the app like this:

<Image x:Name="myImage"
        Stretch="None"
        Width="15"
        Height="15" 
        HorizontalAlignment="Center"
        VerticalAlignment="Center"
        Source="/App1;component/Images/My_Image.png" />

In some cases, in Release builds, the images fail to appear. From what I can see, in Release builds the source can't find the assembly name, so the image fails to load. I verified this by renaming all of the output assemblies in the <assemblyname> tags above to "App1" and it works.

So I've implemented code like this:

private BitmapImage _MyImage;
public BitmapImage MyImage
{
    get { return _MyImage; }
    set
    {
        if (_MyImage != value)
        {
            _MyImage = value;
            RaisePropertyChanged("MyImage");
        }
    }
}

and

        private void SetupBranding()
        {
            var imageFolder = "";

if BRAND_APP1
            imageFolder = "App1";
elif BRAND_APP2
            imageFolder = "App2";
elif BRAND_APP3
            imageFolder = "App3";
elif BRAND_APP4
            imageFolder = "App4";
<h1>endif</h1>

            // Get the assembly name
            string assemblyName = Assembly.GetExecutingAssembly().GetName().Name;

            // Form the path to the assembly's image folder
            var path = $"/{assemblyName};component/Images/Brand/{imageFolder}/My_Image.png";
            MyImage = new BitmapImage(new Uri(path, UriKind.Relative));
        }

This seems to work fine, but I have do do this anywhere I want to use brand-specific images. I'm wondering of there's a better way? Is there a way to handle hard coded pack URI such has:

Source="/App1;component/Images/My_Image.png"

One other concern is that, while most of this is done in the Windows and Views, there are some URI's specified in styles.

Thanks

In theory, theory and practice are the same. But in practice, they never are.”
If it's not broken, fix it until it is.
Everything makes sense in someone's mind.

Gerry Schmitz6-Jun-23 15:52

Gerry Schmitz

6-Jun-23 15:52

Use relative Pack URI's.

Pack URIs - WPF .NET Framework | Microsoft Learn

c# Spotify API not returning correctly.

elfenliedtopfan52-Jun-23 18:03

elfenliedtopfan5

2-Jun-23 18:03

Good morning all,

been writing a little program that when you put a spotify playlist id in it will get the whole playlist

want the name and total songs in the playlist mainly so all songs in the playlist and then total count of all songs

with a bit of hard work managed to get it to deserialize the content but cant seem to get it to return that

what i have currently is this,

so it goes though and get as far as here,

json data returned from spotify api

put it in pastebin link as contains a lot of data

then thought i would use json2c#
to create my structure for me,

and have this in a playlist.cs

<pre lang="C#"><pre>using System;
using System.Collections.Generic;
using System.Text;

namespace Dark_Admin_Panel.Model
{
    public class Playlist
    {
        // Root myDeserializedClass = JsonConvert.DeserializeObject<Root>(myJsonResponse);
        public class AddedBy
        {
            public ExternalUrls external_urls { get; set; }
            public string href { get; set; }
            public string id { get; set; }
            public string type { get; set; }
            public string uri { get; set; }
        }

        public class Album
        {
            public string album_type { get; set; }
            public List<Artist> artists { get; set; }
            public List<string> available_markets { get; set; }
            public ExternalUrls external_urls { get; set; }
            public string href { get; set; }
            public string id { get; set; }
            public List<Image> images { get; set; }
            public string name { get; set; }
            public string release_date { get; set; }
            public string release_date_precision { get; set; }
            public int total_tracks { get; set; }
            public string type { get; set; }
            public string uri { get; set; }
        }

        public class Artist
        {
            public ExternalUrls external_urls { get; set; }
            public string href { get; set; }
            public string id { get; set; }
            public string name { get; set; }
            public string type { get; set; }
            public string uri { get; set; }
        }

        public class ExternalIds
        {
            public string isrc { get; set; }
        }

        public class ExternalUrls
        {
            public string spotify { get; set; }
        }

        public class Followers
        {
            public object href { get; set; }
            public int total { get; set; }
        }

        public class Image
        {
            public int height { get; set; }
            public string url { get; set; }
            public int width { get; set; }
        }

        public class Item
        {
            public DateTime added_at { get; set; }
            public AddedBy added_by { get; set; }
            public bool is_local { get; set; }
            public object primary_color { get; set; }
            public Track track { get; set; }
            public VideoThumbnail video_thumbnail { get; set; }
        }

        public class Owner
        {
            public string display_name { get; set; }
            public ExternalUrls external_urls { get; set; }
            public string href { get; set; }
            public string id { get; set; }
            public string type { get; set; }
            public string uri { get; set; }
        }

        public class Root
        {
            public bool collaborative { get; set; }
            public string description { get; set; }
            public ExternalUrls external_urls { get; set; }
            public Followers followers { get; set; }
            public string href { get; set; }
            public string id { get; set; }
            public List<Image> images { get; set; }
            public string name { get; set; }
            public Owner owner { get; set; }
            public object primary_color { get; set; }
            public bool @public { get; set; }
            public string snapshot_id { get; set; }
            public Tracks tracks { get; set; }
            public string type { get; set; }
            public string uri { get; set; }
        }

        public class Track
        {
            public Album album { get; set; }
            public List<Artist> artists { get; set; }
            public List<string> available_markets { get; set; }
            public int disc_number { get; set; }
            public int duration_ms { get; set; }
            public bool episode { get; set; }
            public bool @explicit { get; set; }
            public ExternalIds external_ids { get; set; }
            public ExternalUrls external_urls { get; set; }
            public string href { get; set; }
            public string id { get; set; }
            public bool is_local { get; set; }
            public string name { get; set; }
            public int popularity { get; set; }
            public string preview_url { get; set; }
            public bool track { get; set; }
            public int track_number { get; set; }
            public string type { get; set; }
            public string uri { get; set; }
        }

        public class Tracks
        {
            public string href { get; set; }
            public List<Item> items { get; set; }
            public int limit { get; set; }
            public object next { get; set; }
            public int offset { get; set; }
            public object previous { get; set; }
            public int total { get; set; }
        }

        public class VideoThumbnail
        {
            public object url { get; set; }
        }

    }
}

and is called via the spotifySearch methord

<pre>using System;
using System.Collections.Generic;
using System.Reflection.Metadata;
using System.Text;
using static Dark_Admin_Panel.Model.SpotifySearch;

namespace Dark_Admin_Panel.Model
{
    public class SpotifySearch
    {
        public class ExternalUrls
        {
            public string spotify { get; set; }
        }

        public class Followers
        {
            public object href { get; set; }
            public int total { get; set; }
        }

        public class ImageSP
        {
            public int width { get; set; }
            public string url { get; set; }
            public int height { get; set; }
        }

        public class Item
        {
            public ExternalUrls external_urls { get; set; }
            public Followers followers { get; set; }
            public List<string> genres { get; set; }
            public string id { get; set; }
            public List<ImageSP> images { get; set; }
            public string name { get; set; }
            public int popularity { get; set; }
            public string type { get; set; }
            public string uri { get; set; }

        }

        public class Artists
        {
            public string href { get; set; }
            public List<Item> items { get; set; }
            public int limit { get; set; }

        }


        //public class playlist
        //{
        //    public string href { get; set; }
        //    public int limit { get; set; }
        //    public List<playlistItems> items { get; set; }
        //    public int total { get; set; }
        //}


        public class PlaylistItem
        {
            public ExternalUrls external_urls { get; set; }
            public string id { get; set; }
            public string name { get; set; }
            public string type { get; set; }
            public List<ImageSP> images { get; set; }

            public Tracks tracks { get; set; }

            public string uri { get; set; }
        }



        public class PlaylistContainer
        {
            public string href { get; set; }
            public List<PlaylistItem> items { get; set; }
            public int total { get; set; }
            public int limit { get; set; }
        }



        public class Tracks
        {
          public string href { get; set; }
          
          public int total { get; set; }



        }

        public class SpotifyResult
        {
            public PlaylistContainer playlists { get; set; }
            public class AddedBy
            {
                public ExternalUrls external_urls { get; set; }
                public string href { get; set; }
                public string id { get; set; }
                public string type { get; set; }
                public string uri { get; set; }
            }

            public class Album
            {
                public string album_type { get; set; }
                public List<Artist> artists { get; set; }
                public List<string> available_markets { get; set; }
                public ExternalUrls external_urls { get; set; }
                public string href { get; set; }
                public string id { get; set; }
                public List<Image> images { get; set; }
                public string name { get; set; }
                public string release_date { get; set; }
                public string release_date_precision { get; set; }
                public int total_tracks { get; set; }
                public string type { get; set; }
                public string uri { get; set; }
            }

            public class Artist
            {
                public ExternalUrls external_urls { get; set; }
                public string href { get; set; }
                public string id { get; set; }
                public string name { get; set; }
                public string type { get; set; }
                public string uri { get; set; }
            }

            public class ExternalIds
            {
                public string isrc { get; set; }
            }

            public class ExternalUrls
            {
                public string spotify { get; set; }
            }

            public class Followers
            {
                public object href { get; set; }
                public int total { get; set; }
            }

            public class Image
            {
                public int height { get; set; }
                public string url { get; set; }
                public int width { get; set; }
            }

            public class Item
            {
                public DateTime added_at { get; set; }
                public AddedBy added_by { get; set; }
                public bool is_local { get; set; }
                public object primary_color { get; set; }
                public Track track { get; set; }
                public VideoThumbnail video_thumbnail { get; set; }
            }

            public class Owner
            {
                public string display_name { get; set; }
                public ExternalUrls external_urls { get; set; }
                public string href { get; set; }
                public string id { get; set; }
                public string type { get; set; }
                public string uri { get; set; }
            }

            public class Root
            {
                public bool collaborative { get; set; }
                public string description { get; set; }
                public ExternalUrls external_urls { get; set; }
                public Followers followers { get; set; }
                public string href { get; set; }
                public string id { get; set; }
                public List<Image> images { get; set; }
                public string name { get; set; }
                public Owner owner { get; set; }
                public object primary_color { get; set; }
                public bool @public { get; set; }
                public string snapshot_id { get; set; }
                public Tracks tracks { get; set; }
                public string type { get; set; }
                public string uri { get; set; }
            }

            public class Track
            {
                public Album album { get; set; }
                public List<Artist> artists { get; set; }
                public List<string> available_markets { get; set; }
                public int disc_number { get; set; }
                public int duration_ms { get; set; }
                public bool episode { get; set; }
                public bool @explicit { get; set; }
                public ExternalIds external_ids { get; set; }
                public ExternalUrls external_urls { get; set; }
                public string href { get; set; }
                public string id { get; set; }
                public bool is_local { get; set; }
                public string name { get; set; }
                public int popularity { get; set; }
                public string preview_url { get; set; }
                public bool track { get; set; }
                public int track_number { get; set; }
                public string type { get; set; }
                public string uri { get; set; }
            }

            public class Tracks
            {
                public string href { get; set; }
                public List<Item> items { get; set; }
                public int limit { get; set; }
                public object next { get; set; }
                public int offset { get; set; }
                public object previous { get; set; }
                public int total { get; set; }
            }

            public class VideoThumbnail
            {
                public object url { get; set; }
            }

            public class SpotifySearch
            {
                public class ExternalUrls
                {
                    public string spotify { get; set; }
                }

                public class Followers
                {
                    public object href { get; set; }
                    public int total { get; set; }
                }

                public class ImageSP
                {
                    public int width { get; set; }
                    public string url { get; set; }
                    public int height { get; set; }
                }

                public class Item
                {
                    public ExternalUrls external_urls { get; set; }
                    public Followers followers { get; set; }
                    public List<string> genres { get; set; }
                    public string id { get; set; }
                    public List<ImageSP> images { get; set; }
                    public string name { get; set; }
                    public int popularity { get; set; }
                    public string type { get; set; }
                    public string uri { get; set; }

                }

                public class Artists
                {
                    public string href { get; set; }
                    public List<Item> items { get; set; }
                    public int limit { get; set; }

                }

                public class PlaylistItem
                {
                    public ExternalUrls external_urls { get; set; }
                    public string id { get; set; }
                    public string name { get; set; }
                    public string type { get; set; }
                    public List<ImageSP> images { get; set; }

                    public Tracks tracks { get; set; }

                    public string uri { get; set; }
                }

                public class PlaylistContainer
                {
                    public string href { get; set; }
                    public List<PlaylistItem> items { get; set; }
                    public int total { get; set; }
                    public int limit { get; set; }
                }

                public class Tracks
                {
                    public string href { get; set; }
                    public int total { get; set; }
                }

                public class SpotifyResult
                {
                    public PlaylistContainer playlists { get; set; }
                }
            }
        }

    }
}

then when the item is searched it uses
search helper
and this is where it returns nothing
however the responce.Content returns all the values,

search helper

<pre>public static SpotifySearch.SpotifyResult SearchArtistOrSong(string searchword)
        {
            var client = new RestClient("https://api.spotify.com/v1/playlists");
            client.AddDefaultHeader("Authorization", $"Bearer {token.access_token}");
            var request = new RestRequest($"{searchword}", Method.Get); // Corrected here
            var response = client.Execute(request);

            if (response.IsSuccessful)
            {
                var result = JsonConvert.DeserializeObject<SpotifySearch.SpotifyResult>(response.Content);
                return result;
            }
            else
            {
                return null;
            }
        }

and the mainwindow.cs

<pre> private void elfentext_KeyUp(object sender, KeyEventArgs e)
        {

            var result = SearchHelper.SearchArtistOrSong(elfentext.Text);
            if (result == null)
            {
                return;
            }

            var listArtist = new List<SpotifySearch.PlaylistItem>();

            if (result?.playlists?.items != null)
            {
                foreach (var item in result.playlists.items)
                {
                    var images = item.images.Any() ? item.images : new List<SpotifySearch.ImageSP>();
                    listArtist.Add(new SpotifySearch.PlaylistItem()
                    {
                        external_urls = item.external_urls,
                        id = item.id,
                        name = item.name,
                        type = item.type,
                        images = images,
                        tracks = item.tracks,
                        uri = item.uri
                    });
                }
            }

            elfenlist.ItemsSource = listArtist;
        }

i managed to get artist working fine before but just playlist returns so much i just not quite sure what i am doing wrong any help would be so much appreciated

thanks in advance elfenliedtopfan5

Re: c# Spotify API not returning correctly.

Pete O'Hanlon4-Jun-23 8:42

Pete O'Hanlon

4-Jun-23 8:42

You have asked this in a forum dedicated to WPF. Your post has nothing to do with this. You should ask this in Q&A.

Advanced TypeScript Programming Projects

Re: c# Spotify API not returning correctly.

jschell5-Jun-23 5:01

jschell

5-Jun-23 5:01

elfenliedtopfan5 wrote:
what i am doing wrong

Perhaps something is eating an exception?
Not clear how you determined that the response content is valid json.

You can also experiment (test) by populating everything in your json objects. Then serialize them to a string. Output that (so you have an example) then deserialize the same thing.

Need help please regarding your awesome WPF MultiComboBox project :)

Member 1160463425-May-23 5:21

Member 11604634

25-May-23 5:21

Hello!

I was wondering how to populate the multicombobox from the backend and not by user, from the parent control.

Scenario, I am using your code base (Multi Select ComboBox in WPF[^]) for user to save items to database.
I now want to allow the user to pull all the items previously selected to re-populate the multicombobox.

I have been trying but with no success.

Many thanks on any advise you can provide!

James

modified 25-May-23 11:47am.

Re: Need help please regarding your awesome WPF MultiComboBox project :)

jeron125-May-23 5:50

jeron1

25-May-23 5:50

At the bottom of the linked article is a place to leave questions or comments to the author.

"the debugger doesn't tell me anything because this code compiles just fine" - random QA comment
"Facebook is where you tell lies to your friends. Twitter is where you tell the truth to strangers." - chriselst
"I don't drink any more... then again, I don't drink any less." - Mike Mullikins uncle

Re: Need help please regarding your awesome WPF MultiComboBox project :)

Richard Deeming25-May-23 21:28

NavigationControl - Part 3

25-May-23 21:28

As Jeron said, the forum at the bottom of the article[^] is the place to post questions about the article.

However, the author hasn't been active since 2014, so it's possible he may not still be here.

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Kevin Marois14-May-23 8:01

Re: NavigationControl - Part 3

14-May-23 8:01

So I am continuing to work on my Navigation Control[^]. See this[^] and this[^]. The code is in this repo[^].

Special thanks to Richard Deeming for all your help so far. I've learned alot from you.

If you look at the image of the control in the first link above, you 'll see 3 sections, with the 3rd still loading. The expanders can be openend either by the user, or by saving & restoring a bool. On the NavigationPane control there's a DP called IsPaneExpanded. This get called with from the user or by the restoring during load.

When the control is being initialized I store the value of the DP.
Fields

// Stores the value of the DP IsPaneExpanded during initialization. See
// comments in the DP IsPaneExpanded 
private bool _isPaneExpanded = false;

// Set to true after the control has finished initializing
private bool _isInitialized = false;

IsPaneExpanded DP

public static readonly DependencyProperty IsPaneExpandedProperty =
            DependencyProperty.Register("IsPaneExpanded",
            typeof(bool),
            typeof(NavigationPane),
            new PropertyMetadata(false, new PropertyChangedCallback(OnIsPaneExpandedChanged)));

public bool IsPaneExpanded
{
    get { return (bool)GetValue(IsPaneExpandedProperty); }
    set { SetValue(IsPaneExpandedProperty, value); }
}

private static async void OnIsPaneExpandedChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
    var control = (NavigationPane)d;

    if (!control._isInitialized)
    {
        // If here, the control is still being initialized. Store the
        // IsPaneExpanded setting for later use when the control's init
        // has finished
        control._isPaneExpanded = control.IsPaneExpanded;

        // Since the control is not loaded, there is nothing to show. But
        // since the IsExpanded can be set from the Window, and it's bound,
        // it's possible for the expander arrow to show open even though
        // there's nothing there. So force the expander to show as collapsed
        control.IsPaneExpanded = false;
    }
    else
    {
        // If here, the control has already been initialized, so go ahead
        // and call load. If here, the user clicked the expander arrow.
        if (control.IsPaneExpanded)
        {
            await control.Load();
        }
    }
}

Then, once initialzation is complete, I check that to see if the control's expander should be expanded.

Problem 1
The problem above is that the _isPaneExpanded is always false by the time it gets here. It IS being set to True in the DP, yet once the code reaches this point, it's false, so the load never happens. Maybe it's because the DP is static and the field isn't?

Problem 2
Another issue I see - I'd like the expander to open visuall FIRST, then call load. The Expander's Expanded event fires AFTER it has opened, but BEFORE the user sees anything visually the load is firing. Nothing changes visually until AFTER the load is complete.

private async void NavigationPane_Initialized(object? sender, EventArgs e)
{
    // If the control's IsPaneExpanded was set from the parent, then
    // the IsPandedExpanded DP would have set _isPaneExpanded = true.
    if (_isPaneExpanded) <==================================================== PROBLEM 1 HERE
    {
        // Now that the control has finished initializing, go ahead
        // and call load

        <=============================== PROBLEM 2 HERE. HOW DO YOU FORCE THE EXPANDER TO SHOW AS OPEN BEFORE LOAD
        await Load();
    }

    _isInitialized = true;
}

If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.

modified 14-May-23 16:37pm.

Richard Deeming14-May-23 21:40

Re: NavigationControl - Part 3

14-May-23 21:40

Problem 1:
The change event for the IsPaneExpanded property sets the IsPaneExpanded property to false if _isInitialized is false. If the property has just changed to true, that will cause the change event to fire again. As a result, the _isPaneExpanded field will be set to true, then immediately set back to false.

Thankfully, WPF won't fire the event if the property is set to the same value; otherwise, you'd end up with infinite recursion.

It would probably be better to use a CoerceValueCallback[^] instead:

public static readonly DependencyProperty IsPaneExpandedProperty =
    DependencyProperty.Register("IsPaneExpanded",
        typeof(bool),
        typeof(NavigationPane),
        new PropertyMetadata(
            defaultValue: false, 
            propertyChangedCallback: new PropertyChangedCallback(OnIsPaneExpandedChanged),
            coerceValueCallback: new CoerceValueCallback(CoerceIsPaneExpanded)
        ));

private static void OnIsPaneExpandedChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
    var control = (NavigationPane)d;
    control._isPaneExpanded = (bool)e.NewValue;
    control.CoerceValue(IsPaneExpandedProperty);
    
    if (control._isInitialized && control._isPaneExpanded)
    {
        _ = control.Load();
    }
}

private static object CoerceIsPaneExpanded(DependencyObject d, object baseValue)
{
    var control = (NavigationPane)d;
    return control._isInitialized ? baseValue : (object)false;
}

Problem 2:
You need to change the _isInitialized field, trigger the change event for the IsPaneExpanded property, then load the data.

private void NavigationPane_Initialized(object? sender, EventArgs e)
{
    _isInitialized = true;
    CoerceValue(IsPaneExpandedProperty);
    
    if (_isPaneExpanded)
    {
        _ = Load();
    }
}

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Kevin Marois15-May-23 17:14

15-May-23 17:14

Thanks, I understand the change you recommened, but it doesn't seem to change anything. I have two different issues. I beleive I solved the first one.

The Projects pane should be expanded on startup BEFORE it loads so the user seees the wait indicator. This bit of code in the MainWindow simulates storing and resetting it from settings later on. if there was an ExpandedExpanded (past-tense) then I could call Load() from there.

Main Window.cs

NavigationPaneInfos = new List<NavigationPaneModel>
{
    new NavigationPaneModel
    {
        Header = "Projects", 
        NavigationItemType = NavigationItemType.Project, 
        DataSource = Functional.Apply(Repository.GetNavigationItems, NavigationItemType.Project),
        IsExpanded = true   // <====== 1. This should force the Projects pane to expand on startup, and that should trigger Load() after the wait indicator is visible
    },

    new NavigationPaneModel
    {
        Header = "Inventory", 
        NavigationItemType = NavigationItemType.Inventory,
        DataSource = Functional.Apply(Repository.GetNavigationItems, NavigationItemType.Inventory),
    },

    new NavigationPaneModel
    {
        Header = "Companies" , 
        NavigationItemType = NavigationItemType.Company,
        DataSource = Functional.Apply(Repository.GetNavigationItems, NavigationItemType.Company),
    },

    new NavigationPaneModel
    {
        Header = "Employees", 
        NavigationItemType = NavigationItemType.Employee,
        DataSource = Functional.Apply(Repository.GetNavigationItems, NavigationItemType.Employee),
    }
};

so, that caused this

private static object CoerceIsPaneExpanded(DependencyObject d, object baseValue)
{
    var control = (NavigationPane)d;
    var newVal = control._isInitialized ? baseValue : (object)false;
    return newVal; //<======= THIS IS NEVER TRUE
}

and

private void NavigationPane_Initialized(object? sender, EventArgs e)
{
    _isInitialized = true;
    CoerceValue(IsPaneExpandedProperty);

    if (_isPaneExpanded) //<====== 2. THIS IS NEVER TRUE
    {
        _ = Load();
    }
}

so, I added this, which correctly sets _isPaneExpanded based off the value set in the main window

private static async void OnNavigationPaneModelChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
    var control = (NavigationPane)d;
    var model = e.NewValue as NavigationPaneModel;
    if (model != null)
    {
        control._isPaneExpanded = model.IsExpanded;
    }
}

This is where the UI is freezing up

private async Task Load()
{
    if (NavigationPaneModel != null && NavigationPaneModel.DataSource != null)
    {
        // 2. This calls the repo and returns data, but it's not async, which is 
        // causing the UI to frees
        var dataSource = NavigationPaneModel.DataSource(); 

        List<NavigationEntity>? data = null;

        if (dataSource != null)
        {
            data = await Task.Run(() => dataSource);
        }

        if (data != null)
        {
            Items = new ObservableCollection<NavigationEntity>(data);
        }
    }
}

so I tried this but....

private async Task Load()
{
    if (NavigationPaneModel != null && NavigationPaneModel.DataSource != null)
    {
        List<NavigationEntity>? data = null;

        await Task.Run(() => 
        {
            // This throws with
            //
            //  "The calling thread cannot access this object because a different thread owns it.'"
            //
            // So I need to figure out how to call the delegate async
            data = NavigationPaneModel.DataSource();
        });

        if (data != null)
        {
            Items = new ObservableCollection<NavigationEntity>(data);
        }
    }
}

So, it seems like all that's left is to get the backend call to fire async. The delegate was set in the UI using

NavigationPaneModel.DataSource = Functional.Apply(Repository.GetNavigationItems, NavigationItemType.Project)

How can I invoke the delegate async from Load()?

I checked my code into the repo.

If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.

Bubbling Event Question

Kevin Marois9-May-23 14:32