What is the best way to activate textures?

Question

C++ / C#

Hello, I have a small question. How to activate textures if I don't know their number? I came up with the idea to get an activated texture and write a big switch, but as I understand it, this is far from the best option. There is also an idea to write a large enum, but this is a so-so idea. Perhaps you can somehow convert the string to an enum value?
PS: I looked at the values ​​of these textures, and another question arose. Is it possible to write like this: 0x84DF+0x0001?