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docs: fix #47146 – improve email validation regex to prevent invalid formats #47285

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docs: fix #47146 – improve email validation regex to prevent invalid formats #47285

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1784ae3
Fix typo 'earch' to 'search' in TOC entry
Gurry-12 Jun 22, 2025
ec5e97f
Merge branch 'dotnet:main' into main
Gurry-12 Jun 23, 2025
f4e9a16
Improve email validation regex to exclude invalid characters like commas
Gurry-12 Jul 10, 2025
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22 changes: 11 additions & 11 deletions docs/standard/base-types/how-to-verify-that-strings-are-in-valid-email-format.md
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Expand Up @@ -61,17 +61,17 @@ The `IsValidEmail` method merely determines whether the email format is valid fo

:::code language="vb" source="snippets/how-to-verify-that-strings-are-in-valid-email-format/vb/RegexUtilities.vb":::

In this example, the regular expression pattern `^[^@\s]+@[^@\s]+\.[^@\s]+$` is interpreted as shown in the following table. The regular expression is compiled using the <xref:System.Text.RegularExpressions.RegexOptions.IgnoreCase?displayProperty=nameWithType> flag.

| Pattern | Description |
|-----------|------------------------------------------------------------------------------------------|
| `^` | Begin the match at the start of the string. |
| `[^@\s]+` | Match one or more occurrences of any character other than the @ character or whitespace. |
| `@` | Match the @ character. |
| `[^@\s]+` | Match one or more occurrences of any character other than the @ character or whitespace. |
| `\.` | Match a single period character. |
| `[^@\s]+` | Match one or more occurrences of any character other than the @ character or whitespace. |
| `$` | End the match at the end of the string. |
In this example, the regular expression pattern `^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$` is used, which better reflects common email rules by excluding invalid characters like commas. The regular expression is compiled using the <xref:System.Text.RegularExpressions.RegexOptions.IgnoreCase?displayProperty=nameWithType> flag.

| Pattern | Description |
|----------------------|-----------------------------------------------------------------------------|
| `^` | Start of the string |
| `[a-zA-Z0-9._%+-]+` | One or more valid characters in the local part (letters, digits, `.`, `_`, `%`, `+`, `-`) |
| `@` | Matches the at-symbol (`@`) |
| `[a-zA-Z0-9.-]+` | One or more valid domain name characters |
| `\.` | Matches a dot (`.`) |
| `[a-zA-Z]{2,}` | Matches a top-level domain of at least two alphabetical characters |
| `$` | End of the string |

> [!IMPORTANT]
> This regular expression isn't intended to cover every aspect of a valid email address. It's provided as an example for you to extend as needed.
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