ASP.NET ASP.NET - Validators RegularExpressionValidator
Example
The RegularExpressionValidator allows validating the input text by matching against a pattern of a regular expression. The regular expression is set in the ValidationExpression property.
The following table summarizes the commonly used syntax constructs for regular expressions:
| Character Escapes | Description |
|---|---|
| \b | Matches a backspace. |
| \t | Matches a tab. |
| \r | Matches a carriage return. |
| \v | Matches a vertical tab. |
| \f | Matches a form feed. |
| \n | Matches a new line. |
| \ | Escape character. |
Apart from single character match, a class of characters could be specified that can be matched, called the metacharacters.
| Metacharacters | Description |
|---|---|
| . | Matches any character except \n. |
| [abcd] | Matches any character in the set. |
| [^abcd] | Excludes any character in the set. |
| [2-7a-mA-M] | Matches any character specified in the range. |
| \w | Matches any alphanumeric character and underscore. |
| \W | Matches any non-word character. |
| \s | Matches whitespace characters like, space, tab, new line etc. |
| \S | Matches any non-whitespace character. |
| \d | Matches any decimal character. |
| \D | Matches any non-decimal character. |
Quantifiers could be added to specify number of times a character could appear.
| Quantifier | Description |
|---|---|
| * | Zero or more matches. |
| + | One or more matches. |
| ? | Zero or one matches. |
| {N} | N matches. |
| {N,} | N or more matches. |
| {N,M} | Between N and M matches. |
The syntax of the control is as given:
<asp:RegularExpressionValidator ID="string" runat="server" ErrorMessage="string"
ValidationExpression="string" ValidationGroup="string">
</asp:RegularExpressionValidator>
