C# Static class vs struct for predefined strings

A co-worker just created the following construction in C# (the example code is simplified). His goal was to shorten the notation for all predefined strings in the rest of the code.

public struct PredefinedStrings
{
    public const string VeryLongName = "Very Long Name";
    public const string AnotherVeryLongName = "Another Very Long Name";
    public const string TheLastVeryLongName = "The Last Very Long Name";
}

public static void MethodThatUsesTheNames()
{
    Console.WriteLine(PredefinedStrings.VeryLongName);
    Console.WriteLine(PredefinedStrings.AnotherVeryLongName);
    Console.WriteLine(PredefinedStrings.TheLastVeryLongName);
}

Although it seems to work fine for him, I can't stop wondering whether he should have used a static class instead of a struct or if there's a more elegant way to achieve this.

What would be the preferred way to do this? Please also explain why.

With the struct solution, there's nothing to stop some other code doing new PredefinedStrings(), which won't do anything bad, but is something it's semantically confusing to allow. With a static class the compiler will forbid creation for you. And it goes without saying that static class is the preferred way of providing constants in the Framework.

edit to add, I said that second part without evidence - I have since searched and reasonably quickly found System.Net.Mime.DispositionTypeNames and System.Net.WebRequestMethods.Http.

I would prefer the strings all being in a resource file and not embedded within the code - primarily for internationalisation reasons. This can then be accessed via a static class with the values as property members.

Besides a static class and struct, why not consider using resource files for constant strings? These can be accessed very easily as SomeNamespace.ResourceName.KeyName, and depending on where they are located in your project can be managed externally without recompiling if need be...

Simple rule of thumb: never use structs until you have no other choice.

Constants have a couple of drawbacks:

only simple types can be used (strings, numerics, etc.)
constants are injected into referencing assemblies. If you recompile assembly with constants and don't recompile assembly that uses constants, you'll get into trouble

I would write your code like this (notice rename refactoring too):

public static class KnownNames
{
    public static readonly string VeryLong = "Very Long Name";
    public static readonly string AnotherVeryLong = "Another Very Long Name";
    public static readonly string TheLastVeryLong = "The Last Very Long Name";
}

There is nothing functionally wrong with this code. But stylistically I agree a static class is better. A static class declares the intent of the type is to only hold static / constant data.

C# Static class vs struct for predefined strings

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