Nothing I have tried so far has worked...
A:
What do you mean by "reporting services function"? An MDX query? That would be "//".
Example:
//Comment
For report expressions, it's "'".
Example:
'Comment
Maximilian Mayerl
2009-09-23 12:18:25
Editing an expression in a matrix control, in an RDL file...
SLC
2009-09-23 12:19:45
Oh, okay. That should be ' then.
Maximilian Mayerl
2009-09-23 12:23:54
+2
A:
To comment out source code that is placed within the code section of the Page Properties of a Reporting Services .rdl file simply place an apostrophe in front like so.
'ADD YOUR CODE HERE
Take a look at the following article on SQL Server Central:
Adding Custom Code to Reporting Services
You can also use an apostrophe to place comments in an Expression withing Reporting Services controls. This only appears to work if the comments come after the expression defintion. For example:
= "Test"
'Add Your comments here
John Sansom
2009-09-23 12:40:47