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。

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

It is worth noting here that one of the most significant differences between conditionally executing code based on #if DEBUG versus if(System.Diagnostics.Debugger.IsAttached) is that the compiler directive changes the code that is compiled. That is, if you have two different statements in an #if DEBUG/#else/#endif conditional block, only one of them will appear in the compiled code. This is an important distinction because it allows you do do things such as conditionally compile method definitions to be public void mymethod() versus internal void mymethod() depending on build type so that you can, for example, run unit tests on debug builds that will not break access control on production builds, or conditionally compile helper functions in debug builds that will not appear in the final code if they would violate security in some way should they escape into the wild. The IsAttached property, on the other hand, does not affect the compiled code. Both sets of code are in all of the builds - the IsAttached condition will only affect what is executed. This by itself can present a security issue.

确保在“项目生成属性”中定义了DEBUG常量。这将启用#if DEBUG。我没有看到预定义的RELEASE常量，所以这可能意味着任何不在DEBUG块中的东西都是RELEASE模式。

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;
    }