Cannot access a disposed object in ASP.NET Core working with DbContext

Bump into this error and found out the reason you cannot spin up a task to run a injected DbContext which normally injected by WebAPI dependency injection of a DbContext.

Solution

Create your dbcontext manually using code below (instead of using DbContext passed in the controller)

	Task.Run(() =>
	{
	var optionsBuilder = new DbContextOptionsBuilder<IDS_ODSContext>();
	optionsBuilder.UseSqlServer("Server=(local);Database=IDS_ODS;Integrated Security=True;MultipleActiveResultSets=True;");
	using (var context = new IDS_ODSContext(optionsBuilder.Options))
	{
	var list = context.VwValuations.ToList();
	var data = list.Select(a => new ViewValuation
	{
	InstrumentId = a.InstrumentId.ToString(),
	GrossMarketValueBase = a.Market_Value_Local_Discount,
	PortfolioId = a.PortfolioId.ToString()
	});
	string json = JsonConvert.SerializeObject(data.ToArray());
	var fileTargetPath = Path.Combine(AppConstant.fileResourceFolder, AppConstant.fileResourceName);
	System.IO.File.WriteAllText(fileTargetPath, json);
	}
	});

view raw dbcontext_dispoise_issue.cs hosted with ❤ by GitHub