System.ArgumentException: The source argument must be a MongoDB IQueryable when trying to use EF Core-style DI with MongoDB

aal1 · 2024-12-23T12:49:22.292Z

I’m working on integrating MongoDB with ASP.NET Core using Entity Framework patterns. Currently, EF Core 8.0.11 provides a clean DI setup for relational databases like this:
builder.Services.AddDbContext(opt => { opt.UseNpgsql(connectionString); });

I attempted to use a similar approach with MongoDB:
builder.Services.AddDbContext(opt => { opt.UseMongoDB(“mongodb://localhost:27017”, “mydatabase”); });

However, when I try to execute a query, I get the following error:
System.ArgumentException: The source argument must be a MongoDB IQueryable. (Parameter ‘source’)

The error occurs in this code:
using var scope = _scopeFactory.CreateScope(); var context = scope.ServiceProvider.GetRequiredService();
// Line below causes the error
MongoProductContext pressureOptionsCollection = context.PressureOptions.AsQueryable(); var pressureOptions = await MongoDB.Driver.Linq.MongoQueryable.FirstOrDefaultAsync( pressureOptionsCollection, po => po.Type == type );

Environment:

.NET 8
EntityFrameworkCore 8.0.11
MongoDB.EntityFrameworkCore 8.2.1
ASP.NET Core Web API project

Thanks!

aal1 · 2024-12-28T13:27:29.756Z

I get it, just need use

var pressureOptions = await Microsoft.EntityFrameworkCore.EntityFrameworkQueryableExtensions.FirstOrDefaultAsync(context.Pressure_options.AsQueryable(), po => po.Type == type);

instead of

var pressureOptions = await MongoDB.Driver.Linq.MongoQueryable.FirstOrDefaultAsync( pressureOptionsCollection, po => po.Type == type );

also this DI works fine

builder.Services.AddDbContext(opt => { opt.UseMongoDB(“mongodb://localhost:27017”, “mydatabase”); });