Issue connecting to MongoDB in release mode C#

Question

I recently setup a MongoDB Collection for the first time. I've created some code that accesses a MongoDB user. Below is the Json file for a good idea of what I'm working with:

{
  "_id": {
    "$oid": "6***********************8"
  },
  "Username": "J",
  "Password": "k"
}

In my C# WinUI application (using Visual Studio 2022), I have code that accesses this data. I used the builtin nuget installer to install MongoDB.Driver V3.1.0 and I have using MongoDB.Driver; declared at the begining of each code file (haven't taken the time to implement global usings). Below is the code I'm using:

using System.Collections.Generic;
using Microsoft.UI.Xaml;
using MongoDB.Bson;
using MongoDB.Bson.Serialization.Attributes;
using MongoDB.Driver;

namespace LearnMongoDBTest
{
    /// <summary>
    /// An empty window that can be used on its own or navigated to within a Frame.
    /// </summary>
    public sealed partial class MainWindow : Window
    {
        private List<Template> templates;

        public MainWindow()
        {
            this.InitializeComponent();
            LoadDB();
        }

        public async void LoadDB()
        {
            var mongoClient = new MongoClient("<MyConnectionString>");
            var database = mongoClient.GetDatabase("CPSUSERS");
            var collection = database.GetCollection<Template>("CPSCollection");

            templates = await collection.Find(new BsonDocument()).Limit(10).ToListAsync();

            LoadLists();
        }

        public void LoadLists()
        {
            foreach (var entry in templates)
            {
                myListBox.Items.Add(entry.Username);
                myListBox2.Items.Add(entry.Password);
            }
        }
    }


    public class Template
    {
        [BsonId]
        public ObjectId Id { get; set; }

        [BsonElement("Username")]
        public string Username { get; set; }

        [BsonElement("Password")]
        public string Password { get; set; }
    }
}

All of that code works perfectly fine in Debug mode. It prints all users to the listboxes. However, when I switch the mode to release, I get a ton of errors in the output log (Exception thrown: 'MongoDB.Driver.MongoConnectionException' in MongoDB.Driver.dll, Exception thrown: 'System.MissingMethodException' in MongoDB.Bson.dll, Exception thrown: 'System.MissingMethodException' in MongoDB.Driver.dll) and I am unable to access the database. I'm quite new to MongoDB so any help is appreciated.

Answer 1

In the .csproj file of your WinUI 3 application, add:

<PropertyGroup>
   <PublishTrimmed>false</PublishTrimmed>
</PropertyGroup>

Open your project in VS 2022 and right click project in solution explorer: Properties > Build > Publish > Uncheck Publish trimmed.

---

The trimming optimization feature of VS 2022 (which only runs in release mode) trims necessary methods in the MongoDB.Driver dll file which causes the connection to the database to fail.