C# 5.0 – Caller Information

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C# 5.0 has some new features which can aid us in debugging and logging.

Take a look at this code below on how we do logging prior to C# 5.0. Here we have the need of logging the details of the call made to MethodB()

 1  class Program
 2     {
 3         static void Main(string[] args)
 4         {
 5             InsertToLog("Main");
 6             MethodB();
 7             MethodA();
 8 
 9             Console.ReadKey();
10         }
11 
12         private static void MethodA()
13         {
14             InsertToLog("MethodA");
15             MethodB();
16         }
17 
18         private static void MethodB()
19         {
20         }
21 
22         private static void InsertToLog(string methodName)
23         {
24             Console.WriteLine("{0} called MethodB at {1} ", methodName, DateTime.Now);
25         }
26     }

In the above code all the methods who call the MethodB() has to make a call to InsertToLog(string methodName). This has 2 major problems.

1) Code repetition

2) Very easily one can miss a call (simply forget to call InsertToLog)

So it would be nice to have the InsertToLog method inside MethodB and if we can pass the caller information to MethodB.

C# 5.0 has this feature. Look at the code below.

 1 class Program
 2     {
 3         static void Main(string[] args)
 4         {
 5             //InsertToLog("Main");
 6             MethodB();
 7             MethodA();
 8 
 9             Console.ReadKey();
10         }
11 
12         private static void MethodA()
13         {
14             //InsertToLog("MethodA");
15             MethodB();
16         }
17 
18         private static void MethodB(
19             [CallerMemberName] string memberName = "",
20             [CallerFilePath] string filepath = "",
21             [CallerLineNumber] int linenumber = 0)
22         {
23             InsertToLog(memberName,filepath,linenumber);
24         }
25 
26         private static void InsertToLog(string methodName, string filepath, int linenumber)
27         {
28             Console.WriteLine("{0} called MethodB at {1} from {2} on line number {3}", methodName, DateTime.Now,filepath,linenumber);
29         }
30     }

In order to use the caller information you have add the following reference.

  

using System.Runtime.CompilerServices;

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