Kasper de Jonge PowerPivot Blog

I think all business users want to see alternating colors in on  rows from your tablix. This is not a default function in reporting. After a evening of searching the internet and playing around i found the answer thanks to a post by Teo Lachev here: http://social.msdn.microsoft.com/forums/en-US/sqlreportingservices/thread/18b5a5f7-7304-4d61-821e-7faa344ce964/

How does it work:

 The solution takes advantage of the expression evaluation rules in RS 2008 that have changed as a result of the new on-demand processing model. As a result, state in class-level instance variables is discarded as you page through the report which makes maintaining state trickier between page requests. However, RS 2008 introduces report variables that guarantee one-time evaluation semantics.

1. The report has a EvenRow code-behind function that toggles each time it’s executed.
2. In the Category group (double-click it to access its properties), a EvenRow group level variable is defined that invokes the EvenRow function once per each group instance.

The rest is easy. I set the BackgroundColor property for each textbox to use this variable.

 Practical:

• Go to report properties and then add the evenrow function to the Code box (just a simple state toggler):
  Public _evenRow As Boolean
  Public Function EvenRow() As Boolean
      _evenRow = Not _evenRow
      return _evenRow
  End Function
• Go to the row group properties you want to alternate, go to variables, add the variable “EvenRow” with the function “=Code.EvenRow()”, this will toggle each time the row is called upon
• Now go to the text box properties of the row in the group you want to alternate, go to fill, fill color and add the function “=IIF(Variables!EvenRow.Value=true,”Red”,”Green”)”

Thats it the background color will alternate each time a new group element is started and this is the result: