Why wasn't C# designed with 'const' for variables and methods?

Answer 1

I suspect the first sentence of your question answers it.

Answer 2

I believe you can declare variables as const in C#. static as well, if you feel the need.

http://msdn.microsoft.com/en-us/library/e6w8fe1b(VS.71).aspx

Answer 3

A const performs a compile time substitution of the value wherever it is used and therefore doesn't have any runtime meaning. In general what you propose for const objects would be very difficult for the compiler to determine (if a method will modify the object or not). Your proposal to use a const keyword as an access modifier also then puts burden on the writer and you are still left with a problem of verifying of something does or does not modify the object. Also you are imposing something on the object that does not have a meaning in all contexts. What does it mean if the method is const but you aren't using it as a const object? The functionality you want is usually accomplished by implementing an interface and only exposing the "read-only" parts of the class.