RegularExpression DataAnnotation验证HTML标签

Question

This regular expression validates html tags that include attributes could someone correct this code to work in C# RegularExpression. The problem with this expression is the quotes it stops at the first quote because it's part of the expression doesn't any one know how to fix this or does anyone have an alternative. PS does anyone know of a C# .net regular expression site to test their expressions

Here is the code:

[RegularExpression(@"</?\w+((\s+\w+(\s*=\s*(?:".*?"|'.*?'|[^'">\s]+))?)+\s*|\s*)/?>")]

this is the validation output after adding double quotes to th expression

 data-val-regex-pattern="</?\w+((\s+\w+(\s*=\s*(?:".*?"|'.*?'|[^'">\s]+))?)+\s*|\s*)/?>"

Answer 1

It sounds like your issue is that the string literal doesn't compile as valid C#. When using verbatim string literals (string literals that begin with @ ) you can escape " characters by simply doubling them, "" . Your code should look like:

[RegularExpression(@"</?\w+((\s+\w+(\s*=\s*(?:"".*?""|'.*?'|[^'"">\s]+))?)+\s*|\s*)/?>")]

Further Reading

• string (C# Reference)

However, I'd recommend tweaking the pattern slightly, like this:

[RegularExpression(@"</?\w+((\s+\w+(\s*=\s*(?:""[^""]*""|'[^']*'|[^'"">\s]+))?)+\s*|\s*)/?>")]

Which actually represents the pattern:

</?\w+((\s+\w+(\s*=\s*(?:"[^"]*"|'[^']*'|[^'">\s]+))?)+\s*|\s*)/?>

If this pattern were later converted to html it would look something like this:

</?\w+((\s+\w+(\s*=\s*(?:"[^"]*"|'[^']*'|[^'">\s]+))?)+\s*|\s*)/?>

• < represents an encoded < character
• " represents an encoded " character
• ' represents an encoded ' character