如何从文件名生成安全的类名？

Question

I'm trying to produce some dynamically compiled code with the Razor engine, and I want to name the generated classes according to their source file names to help understand where a piece of generated code comes from.

For example, I would expect the file C:\\source\\Foo.cs to be compile with the name Foo .

Given that I have the path to the source file being compiled, is there a way to generate a valid C# identifier based on the file name?

Answer 1

According to the C# spec, the following rules must be adhered to when creating identifiers:

• An identifier must start with a letter or an underscore
• After the first character, it may contain numbers, letters, connectors, etc
• If the identifier is a keyword, it must be prepended with “@”

This helper will satisfy those conditions:

private static string GenerateClassName(string value)
{
    string className = CultureInfo.CurrentCulture.TextInfo.ToTitleCase(value);
    bool isValid = Microsoft.CSharp.CSharpCodeProvider.CreateProvider("C#").IsValidIdentifier(className);

    if (!isValid)
    { 
        // File name contains invalid chars, remove them
        Regex regex = new Regex(@"[^\p{Ll}\p{Lu}\p{Lt}\p{Lo}\p{Nd}\p{Nl}\p{Mn}\p{Mc}\p{Cf}\p{Pc}\p{Lm}]");
        className = regex.Replace(className, "");

        // Class name doesn't begin with a letter, insert an underscore
        if (!char.IsLetter(className, 0))
        {
            className = className.Insert(0, "_");
        }
    }

    return className.Replace(" ", string.Empty);
}

It first converts the file name to camel case (personal preference), it then uses IsValidIdentifier to determine if the file name is already valid for a class name.

If not, it will remove all invalid characters based on the unicode character classes . It then checks whether the file name starts with a letter, if it does, it prepends an _ to fix it.

Finally, I remove all whitespace (even though it would still be a valid identifier with it).

Answer 2

First, you need to extract the File-Name, for example with:

Path.GetFileNameWithoutExtension

Then you have to follow all rules, ac#-class name has. For example

1. Starting with a letter or _
2. i would remove all other characters than _ AND az AND 0-9

This should be all!

Answer 3

您是否看过密码保护区-http: //msdn.microsoft.com/zh-cn/library/ms404245( v=vs.110) .aspx ？

Answer 4

Take the path, replace the invalid characters like \\ with let's say _ and you're done.

If you prefer shorter names, you could take the path, transform it to lowercase and take a hash value.

Some code sample:

var className = pathIncludingFilename.ToLowerSinceCasingIsNotRelevant().SomeHashFunctionLikeSha1OrPartOfIt() + filename.RemoveInvalidCharactersLikeWhitespace();

The result may look like this:

123a3b6b22foo

The hash should ensure unique names, the filename makes it easier to correlate.