Where to specify preprocessor directives in visual studio?

Question

Trying to define a preprocessor directives in the Visual studio 2012.

#define FLAG
....
#endif

But not sure, where to include this FLAG in visual studio - C#. I remember specifying something like this in C++ projects.

Any thoughts ?

Answer 1

You have two options as to where to define it:

1. Code file level - In the beginning of the file write #define FLAG. You cannot place anything else (other than comments and blank lines) before define directives. As Ron Beyer points out, a directive defined in a file exists only for that file.

2. Project level - Right click in the project in Solution Explorer, select Properties, then the Build tab, then look at Conditional compilation symbols. Then one can define several comma-separated symbols there such as: FLAG,FOO,BAR. Note that this symbols list is project configuration dependent (there is a configuration selector in the same tab).

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Note as mentioned in the comments, define does not work in C# the same way that it does in C. In C# you just declare that the symbol exists, but you can't assign a value to it. Hence the only use for these symbols is for #if FLAG directives and for the Conditional attribute.