Ado.net (4.5): How to efficiently determine empty result set using async API’s

Question

I’m confused a bit on how to tell if a reader has rows (the docs don’t it make any clearer…)

Single empty result set:

var rc = await reader.ReadAsync();

I assume rc == true means I have rows so it’s not necessary to check reader.HasRows again.

But what about multiple result sets?

var rc = await reader.NextResultAsync();
Does rc == true mean I have rows?
What’s the return value semantics?
Do I need to test the next call to reader.ReadAsync() again? or should I check reader.HasRows before advancing the reader?

So basically, what’s the best practice to exit early?

10x

---

itai

Answer 1

Hi Itai,

I'll move this thread to ADO.NET forum for more support.

Thanks for your support and understanding!

---

Iric Wen
TechNet Community Support

Answer 2

Hi Itai,

Welcome to the MSDN forum.

Please check this blog about Using SqlDataReader’s new async methods in .Net 4.5: http://blogs.msdn.com/b/adonet/archive/2012/04/20/using-sqldatareader-s-new-async-methods-in-net-4-5-beta.aspx

Here is an example to help you to understand: http://blogs.msdn.com/b/adonet/archive/2012/07/15/using-sqldatareader-s-new-async-methods-in-net-4-5-beta-part-2-examples.aspx

Good day.

---

Alexander Sun [MSFT]
MSDN Community Support | Feedback to us
Develop and promote your apps in Windows Store
Please remember to mark the replies as answers if they help and unmark them if they provide no help.