如果您试图使用为构建类型定义的变量，您应该删除这两行…

#define DEBUG  
#define RELEASE 

．.． 这将导致#if (DEBUG)始终为真。

RELEASE也没有默认的条件编译符号。如果您想定义一个转到项目属性，单击Build选项卡，然后将RELEASE添加到General标题下的Conditional编译符号文本框中。

另一个选择是这样做……

#if DEBUG
    Console.WriteLine("Debug");
#else
    Console.WriteLine("Release");
#endif

我更喜欢这样检查它，而不是寻找#define指令:

if (System.Diagnostics.Debugger.IsAttached)
{
   //...
}
else
{
   //...
}

需要注意的是，您当然可以在调试模式下编译和部署一些东西，但仍然没有附加调试器。

我不是#if之类的东西的超级粉丝，特别是如果你把它散布在你的代码库中，因为如果你不小心，它会给你带来调试构建通过但发布构建失败的问题。

下面是我想出的(灵感来自c#中的#ifdef):

public interface IDebuggingService
{
    bool RunningInDebugMode();
}

public class DebuggingService : IDebuggingService
{
    private bool debugging;

    public bool RunningInDebugMode()
    {
        //#if DEBUG
        //return true;
        //#else
        //return false;
        //#endif
        WellAreWe();
        return debugging;
    }

    [Conditional("DEBUG")]
    private void WellAreWe()
    {
        debugging = true;
    }
}

名称空间

using System.Resources;
using System.Diagnostics;

方法

   private static bool IsDebug()
    {
        object[] customAttributes = Assembly.GetExecutingAssembly().GetCustomAttributes(typeof(DebuggableAttribute), false);
        if ((customAttributes != null) && (customAttributes.Length == 1))
        {
            DebuggableAttribute attribute = customAttributes[0] as DebuggableAttribute;
            return (attribute.IsJITOptimizerDisabled && attribute.IsJITTrackingEnabled);
        }
        return false;
    }

Since the purpose of these COMPILER directives are to tell the compiler NOT to include code, debug code,beta code, or perhaps code that is needed by all of your end users, except say those the advertising department, i.e. #Define AdDept you want to be able include or remove them based on your needs. Without having to change your source code if for example a non AdDept merges into the AdDept. Then all that needs to be done is to include the #AdDept directive in the compiler options properties page of an existing version of the program and do a compile and wa la! the merged program's code springs alive!.

对于还没有准备好进入黄金时段的新流程，或者在发布之前不能在代码中活动的新流程，您可能还想使用声明式。

总之，我就是这么做的。

删除顶部的定义

#if DEBUG
        Console.WriteLine("Mode=Debug"); 
#else
        Console.WriteLine("Mode=Release"); 
#endif