Dude sippin, he's trying to learn C# not delphi...don't confuse him
As for all your C# Questions:
Q: is there any other things for C#, such as better compilers, like there are for C, C++, and many other programming languages?
A: No. There is one compiler, and that's it. It's the .NET Framework SDK that I gave you the link for.
Q:How good is C# for programming games?
A:If you've got the know-how it's possible. You could make games just like in commercial games. Really anything is possible because you can use DirectX (also you could use OpenGL if that's what you like better). Granted it will take a long time to learn HOW to make games, but that is true for any languages. In fact, it is easier to make a game in C# than it is in C++ or C.
Q:How did you learn C#?
A:I read lots of books and tutorials on C#. I bought some, borrowed some, stuff like that. I also practiced making different things with it daily.
Q:What do you use to compile your C# code?
A:After you've downloaded the .NET SDK (in the link I provided you in one of my last posts) you can either download an IDE (such as SharpDevelope, or some of the others from the company Antechinus) and that will do the work behind the scenes. Or you can use your command line. There are plenty of tutorials on google about how to do that. Actually I'd search MS's website for tutorials....just search for "Compiling C# Programs"
Q:Also, SharpDevelop doesn't work for me. Is there any other (good) text editor that I can use
A: What OS are you using? Because SharpDevelop should work for just about any OS. Also some other good IDE's are ones from Antechinus at this stie:
http://www.c-point.com/csharp.htm
Or you could buy a student version of Visual C# from MS. Which is what I'd recomend, if you don't mind spending about $50. But if now, those free ones are good too.
Q:What's a codebase?
A: It's a big databse of examples, source code and tutorials.
Q:What is delphi?
A: It's another programming language....but if you're wanting to make games, it won't be the best language for you. C# would own it
Hope all that helps.