Effective C# 学习笔记（四）使用Conditional Attributes 替代 #if

用法

[Conditional("DEBUG"),

Conditional("TRACE")]

private void CheckState()

{

// Grab the name of the calling routine:

string methodName =

new StackTrace().GetFrame(1).GetMethod().Name;

Trace.WriteLine("Entering CheckState for Person:");

Trace.Write("\tcalled by ");

Trace.WriteLine(methodName);

Debug.Assert(lastName != null,

methodName,

"Last Name cannot be null");

Debug.Assert(lastName.Length > 0,

methodName,

"Last Name cannot be blank");

Debug.Assert(firstName != null,

methodName,

"First Name cannot be null");

Debug.Assert(firstName.Length > 0,

methodName,

"First Name cannot be blank");

Trace.WriteLine("Exiting CheckState for Person");

 

}

private void CheckStateBad()

{

// The Old way:

#if BOTH

Trace.WriteLine("Entering CheckState for Person");

// Grab the name of the calling routine:

string methodName =

new StackTrace().GetFrame(1).GetMethod().Name;

Debug.Assert(lastName != null,

methodName,

"Last Name cannot be null");

Debug.Assert(lastName.Length > 0,

methodName,

"Last Name cannot be blank");

 

Debug.Assert(firstName != null,

methodName,

"First Name cannot be null");

Debug.Assert(firstName.Length > 0,

methodName,

"First Name cannot be blank");

Trace.WriteLine("Exiting CheckState for Person");

#endif

}

 

定义组合变量

#if ( VAR1 && VAR2 )

#define BOTH

#endif