Sanitizing a String for a Property Name

Question

Problem

I need to sanitize a collection of Strings from user input to a valid property name.

Context

We have a DataGrid that works with runtime generated classes. These classes are generated based on some parameters. Parameter names are converted into Properties. Some of these parameter names are from user input. We implemented this and it all seemed to work great. Our logic to sanitizing strings was to only allow numbers and letters and convert the rest to an X.

const string regexPattern = @"[^a-zA-Z0-9]";
return ("X" + Regex.Replace(input, regexPattern, "X")); //prefix with X in case the name starts with a number

The property names were always correct and we stored the original string in a dictionary so we could still show a user friendly parameter name.

However, where the trouble starts is when a string only differs in illegal characters like this:

Parameter Name

Parameter_Name

These were both converted into:

ParameterXName

A solution would be to just generate some safe, unrelated names like A, B C. etc. But I would prefer the name to still be recognizable in debug. Unless it's too complicated to implement this behavior of course.

I looked at other questions on StackOverflow, but they all seem to remove illegal characters, which has the same problem.

I feel like I'm reinventing the wheel. Is there some standard solution or trick for this?

Answer 1

I can suggest to change algorithm of generating safe, unrelated and recognizable names.

In c# _ is valid symbol for member names. Replace all invalid symbols (chr) not with X but with "_"+(short)chr+"_".

demo

public class Program
{
    public static void Main()
    {
        string [] props = {"Parameter Name", "Parameter_Name"};

        var validNames = props.Select(s=>Sanitize(s)).ToList();
        Console.WriteLine(String.Join(Environment.NewLine, validNames));
    }

    private static string Sanitize(string s)
    {
        return String.Join("", s.AsEnumerable()
                                .Select(chr => Char.IsLetter(chr) || Char.IsDigit(chr)
                                               ? chr.ToString()      // valid symbol
                                               : "_"+(short)chr+"_") // numeric code for invalid symbol
                          );
    }
}

prints

Parameter_32_Name
Parameter_95_Name