如何在 C# 中使用 #undef 指令?
csharpprogrammingserver side programming更新于 2025/7/13 0:22:17
#undef 指令允许您取消定义符号。语法如下:−
#undef SYMBOL
例如:
#undef One
与 #if 指令一起使用时，结果为 false。我们来看一个例子。 −
示例
#define One
#undef Two
using System;
namespace Demo {
class Program {
static void Main(string[] args) {
#if (One && TWO)
Console.WriteLine("Both are defined");
#elif (ONE && !TWO)
Console.WriteLine("ONE is defined and TWO is undefined");
#elif (!ONE && TWO)
Console.WriteLine("ONE is defined and TWO is undefined");
#else
Console.WriteLine("Both are undefined");
#endif
}
}
}
输出
Both are undefined
