.Net - Strategies to avoid magic string

Melursus picture Melursus · Jul 8, 2010 · Viewed 7.9k times · Source

In code at work, we have many uses of magic strings like the following code snippet:

if (user.HasRight("Profile.View")) {...}

So there are many places where we pass a string as a parameter to see if the user has a specific right. I don't like that because that generates a lot of magic strings.

What would be a better way of doing it?

Enum, Constant, class ?

Answer

Justin Niessner picture Justin Niessner · Jul 8, 2010

In that specific case, use an Enum. There will be no magic strings and if the Enum changes (in a way that would break the magic strings solution), the app will no longer compile.

public enum ProfilePermissions
{
    View,
    Create,
    Edit,
    Delete
}

Then you can simply have:

if(user.HasRight(ProfilePermissions.View)) { }

You could also use a class, but then you limit yourself when it comes to more complex scenarios. For instance, a simple change of the Enumeration to something like:

public enum ProfilePermissions
{
    View = 1,
    Create = 2,
    Edit = 4,
    Delete = 8
}

Would allow you to use bitwise operators for more complex permissions (for example, a situation where a user needs either Create or Delete):

if(user.HasRight(ProfilePermissions.Create | ProfilePermissions.Delete));