Yes, you can create your own "EF-like" wrapper for MongoDB in C# by building a custom abstraction layer over MongoDB operations. This could allow you to query, insert, update, and delete MongoDB documents in a manner similar to how Entity Framework works with SQL databases.

Here’s a simple approach to creating your own basic "EF-like" functionality for MongoDB using the MongoDB.Driver library.

Steps to Create a MongoDB EF-like Abstraction:

Create a base class for MongoDB context: This class will handle the connection to the MongoDB database and provide generic methods for interacting with MongoDB collections.

using MongoDB.Driver;
using System;
using System.Collections.Generic;
using System.Linq.Expressions;

public class MongoDbContext
{
    private readonly IMongoDatabase _database;

    public MongoDbContext(string connectionString, string databaseName)
    {
        var client = new MongoClient(connectionString);
        _database = client.GetDatabase(databaseName);
    }

    public IMongoCollection<T> GetCollection<T>(string collectionName)
    {
        return _database.GetCollection<T>(collectionName);
    }

    public List<T> GetAll<T>(string collectionName)
    {
        var collection = GetCollection<T>(collectionName);
        return collection.Find(FilterDefinition<T>.Empty).ToList();
    }

    public T Find<T>(string collectionName, Expression<Func<T, bool>> filter)
    {
        var collection = GetCollection<T>(collectionName);
        return collection.Find(filter).FirstOrDefault();
    }

    public void Insert<T>(string collectionName, T document)
    {
        var collection = GetCollection<T>(collectionName);
        collection.InsertOne(document);
    }

    public void Update<T>(string collectionName, Expression<Func<T, bool>> filter, UpdateDefinition<T> update)
    {
        var collection = GetCollection<T>(collectionName);
        collection.UpdateOne(filter, update);
    }

    public void Delete<T>(string collectionName, Expression<Func<T, bool>> filter)
    {
        var collection = GetCollection<T>(collectionName);
        collection.DeleteOne(filter);
    }
}

Create your models: Define C# models that represent the MongoDB documents, similar to how Entity Framework uses classes to represent database tables.

public class User
{
    public string Id { get; set; }
    public string Name { get; set; }
    public int Age { get; set; }
}

Usage Example: You can now use your MongoDbContext to interact with MongoDB in a similar way to how you’d use Entity Framework to interact with a SQL database.

class Program
{
    static void Main(string[] args)
    {
        var context = new MongoDbContext("mongodb://localhost:27017", "MyDatabase");

        // Insert a document
        var user = new User { Name = "John Doe", Age = 30 };
        context.Insert("Users", user);

        // Find a document
        var foundUser = context.Find<User>("Users", u => u.Name == "John Doe");
        Console.WriteLine($"Found user: {foundUser.Name}, Age: {foundUser.Age}");

        // Update a document
        var update = Builders<User>.Update.Set(u => u.Age, 31);
        context.Update("Users", u => u.Name == "John Doe", update);

        // Delete a document
        context.Delete<User>("Users", u => u.Name == "John Doe");

        // Get all documents
        var users = context.GetAll<User>("Users");
        foreach (var u in users)
        {
            Console.WriteLine($"User: {u.Name}, Age: {u.Age}");
        }
    }
}

What this custom wrapper provides:

• Basic CRUD operations: Create, Read, Update, Delete operations are handled through methods like Insert(), Find(), Update(), and Delete().
• LINQ support: You can use LINQ queries for filtering and retrieving documents, much like how Entity Framework works.
• Generic operations: The methods are generic so you can use the same context class for multiple document types.

Enhancements:

• Transactions: MongoDB supports multi-document transactions in replica sets. You can extend this framework to support transactions by using the StartTransaction and CommitTransaction methods.
• Migrations: If you want schema migrations like EF, you'll need to implement a custom solution for versioning and updating your MongoDB schema.
• Validation: Add features like data validation, validation attributes, or model mapping.

This basic structure can be extended to provide more advanced features like lazy loading, auditing, or change tracking, similar to what Entity Framework offers.