如何在C＃visual studio中定义预处理器符号

Question

Sorry if my terminology is wrong. I wrote #if TEST_APP in my code. Now i would like to define TEST_APP. How do i set it using visual studios 2010? This is a windows form application.

Bonus if you can tell me the name of the symbol that is set in a winform project and in a web project

Answer 1

In visual studio solution explorer, right click on a project and click Properties. Open the build tab and you will see a field "Conditional compilation symbols". This is a comma separated list, or space separated. There are also 2 checkboxes for commonly used symbols, DEBUG and TRACE.

For your web projects you could set the field to "WEB_PROJECT" and winforms to "WINFORMS_PROJECT"

Answer 2

In the Build tab of the properties page for the project, look for the "Conditional compilation symbols" setting.

I don't believe there are any different symbols defined by default for web and winform applications. Bear in mind this is set for the project itself, and won't affect any class libraries - so I'd expect any code within a project to really know whether it's in a Windows application or not to start with. What were you thinking of using this for?

Answer 3

Method 1:

#define TEST_APP true
#if TEST_APP == true
#endif

Method 2:

#define TEST_APP
#if defined(TEST_APP)
#endif

Source: MSDN

Answer 4

If you need your conditional compilation to dynamically reflect the build or environment conditions, check my answer to How do I set a conditional compile variable on StackOverflow. I show how to enable conditional compilation based on ambient conditions, such as C# language version , so that you can write code like this:

#if CSHARP7
    ref T pi = ref rg[i], pj = ref rg[j];
    var t = pi;                    // swap elements: managed pointers
    pi = pj;
    pj = t;
#else
    var t = rg[i];                 // swap elements: clunky
    rg[i] = rg[j];
    rg[j] = t;
#endif