Async await how to use return values

Question

I have a windows service that I have inherited from another developer, it runs very slow and has numerous slow call to the eBay API. I wish to speed it up without too much refac

Answer 1

Your async method lacks of await operators and will run synchronously. while you are calling non blocking API you could use Task.Run() to do cpu-bound work on background thread.

public async Task ProcessAdditionalProductDetialsAsync(ItemType oItem)
{
    return await Task.Run(() =>
    {
        String additionalProductDetails = string.Empty;

        if (oItem.ItemSpecifics.Count > 0)
        {
            foreach (NameValueListType nvl in oItem.ItemSpecifics)
            {
                if (nvl.Value.Count > 0)
                {
                    foreach (string s in nvl.Value)
                    {
                        additionalProductDetails += "
" + nvl.Name + ": " + s + "
";
                    }
                }
            }
        }
        return additionalProductDetails;
    });
}

and get result

var detail = await ProcessAdditionalProductDetialsAsync(itemType);
var result = ProcessAdditionalProductDetialsAsync(itemType).Result;