Where to specify preprocessor directives in visual studio? - c#

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 ?

You have two options as to where to define it:
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.
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).
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.

For some reason, when properties clicked, nothing happened for me. So I did the following. And it worked.
Open your csproj project file using text editor and add your preprocessor compiler directives in between these.
<DefineConstants>
HERE!!!
</DefineConstants>

Related

Preprocessor directive cannot be put in AND in C#

I need to put some code under a preprocessor directive.
such directives can be defined in different projects.
My situation is the following:
File Constants.cs (which is in project Proj1Dll.csproj)
#define DEV
... rest of the code
File Page1.cs (which is in project MainProj.csproj, which references Proj1Dll)
#define SHOW_BTN
...
#if (DEV && SHOW_BTN)
public static void Foo()
{
Debug.WriteLine("Both DEV and SHOW_BTN directives are defined");
}
#endif
Such configuration is not working, in the sense that method Foo() is not part of the compilation.
If I check instead #if (DEBUG && SHOW_BTN) everything is fine.
Is there a way to deal with such directives when they are defined in different projects?
Assuming you are using Visual Studio, you can go to the Project Properties, and under the Build tab, you will see 'Conditional compilation symbols'
Put your synbols in here and they will be recognised project wide.
In your example you would put just DEV if you wanted more than one, separate them with semicolon e.g. DEV;SHOW_BTN
If you want something to be solution wide and need only one symbol you can use the configuration manager to create a new configuration specifically for this build and call it what you like - this then gives you the same effect.
(It's why in your example DEBUG works)
Hope that helps.

How to undefine the symbol CONTRACTS_FULL?

Visual Studio defines the CONTRACTS_FULL symbol automatically if
you enable contract checking in the Code Contracts tab of the Project
Properties page.
- C# 5.0 In a Nutshell (page 518)
I'd like to disable/undefine the symbol but it doesn't appear in the Conditional compilation symbols field of the Build tab in the project settings.
(I'm not interested in disabling code-contracts completely! by that I simply mean that setting the contract checking to None is not a solution).
If it matters, the reason I want to do this is because in my release builds I only want to throw on Contract.Requires<TException>, and I don't want to throw ContractException at all.
One "solution" I found is to put #undef CONTRACTS_FULL at the first line of each file, it fixed it but actually doing that would be horrible.
(BTW up until now VS didn't define CONTRACTS_FULL and I had to define it myself, but I guess some setting changed accidentally)
You cannot run the contract tools and undefine the CONTRACTS_FULL symbol. The tools depend on that being defined. Nothing will work if you try to force this. That is why we define the symbol automatically inside the msbuild scripts.
Users of the Code Contract tools should never manually try to define or undefine the CONTRACTS_FULL symbol as it is a tool controlled variable.
I've read that book, and there WAS a contract level that only used Contract.Requires. It was the option before none in there, but it's somewhere in that section in the book, definitely.
However, I can't help you with globally undefing CONTRACTS_FULL. Sorry. I think though that in that contract checking level it's automatically undef'd.
EDIT: Yeah, you need to put it at level one (ReleaseRequired).

Compilation issue in C# .NET

I have the following code (inherited from a contractor):
public partial class StoredProcedures
{
#if NO_THREAD
readonly static String version = "XXXX, Version 1.02, Apr/29/2010";
#else
readonly static String version = "XXXX, Version 0.93, Dec/21/2006";
#endif
I can't seem to find NO_THREAD anywhere else. This is code that compiles and installs as a SQL assembly. Is it something special or am I missing something simple?
Try to check Project Properties->Build->General->Conditional compilation symbols for all Build configurations which you have for the project, It may be there.
Look for a #define statement. See the docs for #if preprocessor conditionals : http://msdn.microsoft.com/en-us/library/4y6tbswk.aspx
If you can't find a
define #NO_THREAD
Anywhere in the code, then it's probably because the contractor was defining the symbol by passing the /define compiler option.
See here for more details (typing from a cell, sorry for the format):
http://msdn.microsoft.com/en-us/library/0feaad6z.aspx
you should probably have a look at the c# pre-processor directives
No_Thread here is a symbol which can be defined by using #define No_Thread and when #define No_Thread is present then #if NO_THREAD will result in true and at compile time readonly static String version = "XXXX, Version 1.02, Apr/29/2010"; this statement will be compiled otherwise the next statement will be compiled.
this is generally used to differentiate between debug and release versions. have you noticed there are 2 versions in VS when you create a new project. if you write something like this somewhere in you code
#if DEBUG
Console.WriteLine("DEBUG VERSION");
#endif
then the string "DEBUG VERSION" would only be printed on the console when the project is in debug mode because the VS inserts a symbol DEBUG if you manually do it using the #define pre-processor then too this line would be compiled
NO_THREAD is a symbol for conditional compilation.
It can come from, #define NO_THREAD, from the project file, or from the nant file (or whatever method you use for building).
If it's defined, the first line of code is counted as part of the C# code. If it isn't, then the second is.
If that's the sole occurence, I'd say it was a hangover from something removed, but if you're uesd to using visual studio to build, then make sure there isn't a build file for nant in case the previous developer used that instead.
This is a conditional compilation symbol. In Visual Studio 2010, these appear on the Build page of your Project Properties in the Conditional compilation symbols text box. Probably one of your Configuration Manager configurations either contains this symbol or has at some point in the past. Presumably, there is another #if somewhere that disables a block of code that uses multiple threads if the NO_THREAD symbol is present.

Can I set a C# preprocessor directive from a central file?

I need to add some logging to my app, and it needs to be in release mode, and I need to make sure that the logging code isn't running in production. Therefore I'd like to use a #define and #if to make sure the log statements are removed when I move to production.
Trouble is, I need the logging in multiple files, and it's a pain to put a #define at the top of every file. Is there a way to have a centralized #define? That way I can remove the single #define rather than a #define from all files(which means I'll almost assuredly forget one).
On the command line, use the /define switch. In Visual Studio, choose the "Build" tab from the properties page for the project and fill in the "Conditional Compilation Symbols" section.
Consider also instead of using conditional compilation, to instead make your logging methods conditional methods. That's a more pleasant-looking alternative. That's how Debug.Assert works; it is a conditional method, so if the debug preprocessor symbol is not defined, the compiler simply removes all calls to the method before code generation.
See also my article on the subject:
http://ericlippert.com/2009/09/10/whats-the-difference-between-conditional-compilation-and-the-conditional-attribute/
Are you using Visual Studio? In the project Properties page, on the "Build" tab, there's a "Conditional compilation symbols" text box.
Yes, this is typically done in your build file, or the script you use which creates your build. You specify it as command-line arguments to MSBuild.
To add to Dave's answer, global conditional compilation symbols can also be specified in Visual.
Right-click on your project and go to Properties
Go to the Build tab
You can specify the symbols that you like (DEBUG is already turned on by default for Debug configurations, so this might actually give you what you want already) for the given configuration, or select "All Configurations" at the top to specify certain symbols for all configurations.
Call the logging everywhere you want.
Define the logging api entry methods with
[Conditional ("DEBUG")]
public void WriteDebugMessage(...)
Build your program in debug mode (which, by default, defines 'DEBUG' in VS). These calls will be part of your assembly.
Build your program in release mode (or - remove the DEBUG symbol from the build definition). These calls are now meaningless no-ops and won't run.
Seems like what you want?

Check using preprocessor if app is a winforms or asp.net

Is this possible to check in assembly what client (winforms app or asp.net page) is running it?
I want to add some methods but only for specific client.
I know, there is predefined DEBUG (#if DEBUG). Where can I find full list, what can I check using preprocessor?
To expand on m0sa's answer, preprocessor directives are basically just a string passed to the compiler.
If you are so inclined, you can add new build configurations (example: instead of Debug/AnyCPU and Release/AnyCPU, you could make WebDebug/AnyCPU, WinformsDebug/AnyCPU, WebRelease/AnyCPU, etc).
Then in the properties page of your project, for each configuration you could provide a value in the 'Conditional compilation symbols' field. For example, for WebDebug and WebRelease, you could provide the conditional symbol WEB. Then, you would be able to use:
#if WEB
using MyNamespace.WebStuff;
#endif
You will need multiple build configurations for that and define different a preprocessor directive for each one. You can set the conditional preprocessor directives in the Build tab of the project Properties page.There are no other directives defined, just the DEBUG directive which you can turn on and off (together with the TRACE directive) in the same tab. Note that DEBUG it is not defined for the "release" build configuration. This is kind of what you will need to do to enable different versions of the assembly to be built.
References:
MSDN
www.davidarno.org <-- see this one for a more visual description

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