Regular Expression for valid domains

Question

Regex(@"@(?:[a-zA-Z0-9-]+\.)+[a-zA-Z]{2,4}$", RegexOptions.Compiled);

Using the above, I want to pass only values like @gmail.com, @xyz.edu, @co.uk etc... But I find that the values like abc@gmail.com (valid email ids) also pass through.

What should I modify?

Answer 1

Domain cannot start with - character.

^(?:[a-zA-Z0-9][a-zA-Z0-9-]*\.)+[a-zA-Z]{2,6}$

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Uri uri = new Uri("http://www.cnn.com/some_link/document.htm");
string url = uri.Host.ToString();

Answer 2

Put a ^ in front of the @.

By the way, why the {2,4} in the end. .travel is a valid top level domain as well.