如何防止Visual Studio 2015的调试器评估带有副作用的静态属性？

Question

I have a singleton class that lazy creates its instance when a property is first called (property side effect).

namespace singletontest2
{
    using System.Diagnostics;
    using MySingleton = Singleton<MyClass>;

    public class MyClass
    {
        private int val = 42;

        public MyClass()
        {
        }
    }

    public static class Singleton<T> where T : new()
    {
        private static T t;

        public static bool IsNull
        {
            get
            {
                return t == null;
            }
        }

        [DebuggerBrowsable(DebuggerBrowsableState.Never)]
        public static T Instance
        {
            get
            {
                if (t == null)
                    t = new T();
                return t;
            }
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            var a = MySingleton.IsNull;
            var d = MySingleton.Instance;
        }
    }
}

If I place a break point in the Instance property getter and on the var d line, the t member will already be initialized when I step into the Instance getter.

If I move the break point from var d to the next line, the t is null when I debug into the Instance getter.

I was under the impression the DebuggerBrowsable attribute would prevent this but it seems to not make any difference.

HOWEVER, if I eliminate the using MySingleton = Singleton<MyClass>; above and call Singleton<MyClass>.Instance; instead of MySingleton.Instance; , then the member t is null when I enter the Instance getter regardless of DebuggerBrowsable which is what I want.

Why is the using directive enabling the debugger to evaluate that property before the code is actually executed?

Answer 1

如此处所提倡的那样，关闭“ 工具”->“选项”->“调试”->“启用属性评估和其他隐式函数调用” ： https : //msdn.microsoft.com/zh-cn/library/0taedcee.aspx