Error 530 validating sender
These are all perfectly valid forms: For most use cases, a false "invalid" is much worse for your users and future proofing than a false "valid".
Here's an article that used to be the accepted answer to this question (that answer has since been deleted).
The third is to suggest a variety of future research opportunities that may assist in developing an understanding and knowledge of the behavioral effects of feedback on auditors.
The literature analysis has significant implications for audit research and practice.
For people suggesting using mail Mail Message(), that thing is WAY to flexible. Generally speaking, a regular expression to validate email addresses is not an easy thing to come up with; at the time of this writing, the syntax of an email address must follow a relatively high number of standards and implementing all of them within a regular expression is practically unfeasible! Disclaimer: I am the lead developer for this component.
Sure, C# will accept the email, but then exchange server will bomb with 5.1.3 runtime error as soon as you try to send the email.
This paper synthesizes the extant feedback literature, focusing on how feedback affects an auditor's learning, performance, and motivation.
Performance feedback is an important component in the auditing environment for ensuring quality control and for developing and coaching staff auditors.
Note that e-mail addresses are more forgiving than you might first assume.
It has a lot more detail and some other ideas of how to solve the problem.
Providing sanity checks is still a good idea for user experience.
Check out my blog post about it for a discussion on the subject and a F# implementation using FParsec.
[/shameless_plug] Here's my answer -- Phil's solution fails for single letter domains like "[email protected]".