Multi-async in Entity Framework 6?

Question

This is my code:

var banner = context.Banners.ToListAsync()
var newsGroup = context.NewsGroups.ToListAsync()
await Task.WhenAll(banner, newsGroup);
         


        

Answer 1

The exception explains clearly that there is only one asynchronous operation per context allowed at a time.

So, you either have to await them one at a time as the error message suggests:

var banner = await context.Banners.ToListAsync();
var newsGroup = await context.NewsGroups.ToListAsync();

Or you can use multiple contexts:

var banner = context1.Banners.ToListAsync();
var newsGroup = context2.NewsGroups.ToListAsync();
await Task.WhenAll(banner, newsGroup);