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Tuesday, 15 February 2011

Regex [x-y] range in reverse order

I started receiving a 'System.ArgumentException' error with a decription of 'parsing "[A-Za-z0-9_- %]+\.(bmp|jpg|jpeg|gif|png)" - [x-y] range in reverse order' after I wrote a C# Regex in my ASP.NET MVC web application.

I was using a RegularExpression Validator in my ASP.NET MVC app but it wasn't having any of it. I was looking at "A-Z" etc thinking IT IS THE RIGHT ORDER!

Turns out it is because I have a hyphen in another part of my regex expression. The one after the underscore.


Turns out hyphens have to appear at either the front or the end of the regular expression - or be escaped with a \. So now I have updated my regular expression from
[RegularExpression(@"[A-Za-z0-9_- %]+\.(bmp|jpg|jpeg|gif|png)")]
[RegularExpression(@"[A-Za-z0-9_ %-]+\.(bmp|jpg|jpeg|gif|png)")]

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  1. Thank you for posting this solution!

  2. Awesome. Exactly what I needed.

  3. Hannes

  4. Thank you. you saved my life


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