Caller Information in C# 5

Caller Information is a new concept introduced in C# 5. It is aimed at providing useful information about where a function was called. It gives information such as:

• Full path of the source file that contains the caller. This is the file path at compile time.
• Line number in the source file at which the method is called.
• Method or property name of the caller.

We specify the following(as optional parameters) attributes in the function definition respectively:

• [CallerMemberName]  a String
• [CallerFilePath]            an Integer
• [CallerLineNumber]     a String

 We use Trace.WriteLine() to output information in the trace window.

here is a C# example:

public void TraceMessage(string message,

        [CallerMemberName] string memberName = "",

        [CallerFilePath] string sourceFilePath = "",

        [CallerLineNumber] int sourceLineNumber = 0)

{

    Trace.WriteLine("message: " + message);

    Trace.WriteLine("member name: " + memberName);

    Trace.WriteLine("source file path: " + sourceFilePath);

    Trace.WriteLine("source line number: " + sourceLineNumber);

} 

You can use the CallerMemberName in:

* Method, Property or Event: They return name of the method, property, or event   from which the call originated. 

* Constructors: They return the String ".ctor" 

* Static Constructors: They return the String ".cctor"

* Destructor: They return the String "Finalize" 

* User Defined Operators or Conversions: They return generated member name 

Whenever we call the TraceMessage() method, it outputs the required information as 

stated above.

Note: Use only with optional parameters. Caller Info does not work when you do not 

use optional parameters.