How to stop evaluation of parameters in calls to d

2019-08-14 21:57发布

I have some code which is littered with debug expressions similar to:

System.Diagnostics.Debug.WriteLine(System.BitConverter.ToString(data.Take(32).ToArray()));

What can I do to prevent the Release version evaluating System.BitConverter.ToString(data.Take(32).ToArray())?

I have added my own debug class that allows me to control calls to WriteLine() based on the level of reporting I want but both methods evaluate the Linq and string conversion even in Release mode (don't they)?

---ADDED LATER---

As I said above there are many of these lines in the code and I don't particularly want to #if DEBUG them all out.

What I want is to know how to avoid evaluating the Linq and the BitConverter, which I assume will be a performance hit, in Release mode.

3条回答
Summer. ? 凉城
2楼-- · 2019-08-14 22:28

You do not have to do anything! The evaluation of the parameters passed to a method that is removed because of the ConditionalAttribute is suppressed already.

See the section The Conditional attribute in the C# Language Specification for authoritative documentation. Quote:

[...] the call (including evaluation of the parameters of the call) is omitted.

To see that the method actually carries the ConditionalAttribute, see Debug.WriteLine(string) documentation.

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甜甜的少女心
3楼-- · 2019-08-14 22:44

#if DEBUG should solve it to you:

#if DEBUG
System.Diagnostics.Debug.WriteLine(System.BitConverter.ToString(data.Take(32).ToArray()));
#endif

More examples here.

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爷的心禁止访问
4楼-- · 2019-08-14 22:48

The answers and comments prompted me to test my supposition that the conversion is evaluated in Release mode.

Console.WriteLine("Console:{0}", ++n);
System.Diagnostics.Debug.WriteLine("Debug:{0}", ++n);
Console.WriteLine("Console:{0}", ++n);

In Release mode I get the output:

Console:1
Console:2

So the Debug line isn't being evaluated at-all in Release mode and I don't need to do any more than use the Debug output and/or add [Conditional("DEBUG")] to my own debug routines (which is already an attribute of the library Debug code).

[Conditional("DEBUG")] - although an attribute of the called function, prevents the function call which prevents the evaluation of parameters to it. It acts in a way very similar to #if DEBUG

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