Dynamic Cell Formatting in SSRS

Early in my Business Intelligence Designer days using other report designer tools, I was all about the data. Get the data onto the report, black and white, never mind fancy fonts or colors. After all, the numbers won’t be any different if you try to make them prettier. A bit like putting lipstick on a pig! Then I came to realize that judicious deviation from the default fonts was not only acceptable, but desirable as evidenced in SQL Server Reporting Services report templates. Sub-total numbers started showing up in a heavier and more prominent font and weight. Grand total number even more so. Such emphasis on the more important numbers on a report help the eyes to quickly identify them as such, leaving the brain to concentrate on other things, such as the numbers themselves. You end up spending more time thinking about the data, and less time finding what you want.

But report cell formatting can go so much further than simply putting more emphasis on numbers at the bottom of the page. With SQL Server Reporting Services, you have the ability to do ‘conditional formatting’, much like can be done in Excel or Access. (If one number is greater than another, format the cell one way, if not, do something else.) To take advantage of the rich formatting options available in SSRS, you need to understand a few basic concepts, and some nuances of Reporting Services.

Know Your Properties

Click on a tablix cell in a report, then click the Properties button.


Note the myriad of properties that can be set just for the cell formatting. Each property, when you go to access its options via the drop-down menu, will have a choice labeled “Expression…”. This is where we will be putting in the ‘conditions’ of the conditional formatting.


Know your Expression Editor, Program Flow expressions, and Property expressions

The Expression Editor in Reporting Services is a powerful tool. For the purposes of our conditional formatting, we’ll be using it to a) examine some value, b) set a Property, and c) supply a default. For the Font Color property of a cell, click the Expression… option below the color palette (see the screen shot above). At this point, the Expression will most likely contain the single word “Black“, assuming you are going with a standard font color. Also note that the work Black is NOT enclosed in double quotes.

 

In the Category list in the lower left, expand the Common Functions node, then click on Program Flow. Note that there are three functions in the Item list:

Choose
IIf
Switch

Each of these can be used effectively for this task, but we’ll stick with the IIf ( ) function as it is probably the easiest to understand. Basically it works like this: IF a certain condition evaluates to TRUE, THEN do what it says in the second section, OTHERWISE, do what it says in the third section (the default). To see it in action, enter the following formula:

=IIf ( 1 = 1 , “Black” , “Red” )

Click OK, then Preview the report. Because 1 always equals 1, the first section evaluates to TRUE, so the second section is used, in this case “Black”. Note that we need to enclose our color names in double quotes in the Expression Editor for this to work. Now edit the formula and replace the 1 = 1 with 1 = 0. The preview will show the cell contents in a red font. Armed with this knowledge, we can replace the 1 = 0 with a more appropriate business condition. Delete the 1 = 0 text, but leave the cursor in that spot. Click on the Fields (DatasetName) node to see a list of fields available for the Dataset. Double click one to have it inserted in the formula. Add some examination criteria for it that makes sense to your business users. Remember that this part of the expression must evaluate to either True or False. Your final Expression might look like this:

= IIf ( Fields!YTD_Sales.Value >= Fields!PriorYear_YTD_Sales.Value , “Black”, “Red” )

The above conditional expression template can also be used to set any other property available. The only trick is to know what to put in place of the “Black” and “Red” components. The easiest way to determine that is to open the list of choices for the property, and use any set of values you see displayed, as long as you enclose them in double quotes in your expression. Shown below is a list of possible values for the Font Weight property

 

Using the same True/False comparison from the previous example, the Font Weight property could contain the expression:

= IIf ( Fields!YTD_Sales.Value >= Fields!PriorYear_YTD_Sales.Value , “Bold”, “Normal” )

Font Size is a little trickier as it does not list any valid values. Just know that “8pt” is an 8 point font, “10pt” is 10 point, and so on.

Other Conditional functions

We skipped over the Choose () and Switch () functions, but they operate in a similar manner to IIf(). They return a value based on some comparison. Microsoft’s example of the Choose() function leaves out one simple element: the return value. Sure, it is nice to show the function in use:

=Choose (2, “13”, “15”, “21)

But it would be even better to explain that the function would be ‘choosing’ the second option, which is “15”. How could we use this in a report? Suppose your Salespeople are ranked on performance, and that ranking is available as a report field as an integer. You could select a Font Weight based on the ranking as follows:

= Choose ( Fields!EmployeeRank.Value, “Heavy”, “ExtraBold”, “Bold”, “Semibold”, “Medium”, “Normal”)

The Switch() function lets you list ‘comparison/return’ pairs, all separated by commas, and the function will take the return value that matches the first comparison that evaluates to True. The basic format for this function is:

= Switch ( Comparison 2, Return Value 1, Comparison 2, Return Value 2, … Comparison N, Return Value N )

A Font Size expression could be written as:

= Switch ( Fields!EmployeeLevel.Value = “Manager”, “16pt”,
Fields!AnnualSales.Value <= Fields!SalesGoal.Value, “14pt”,
Fields!AnnualSales.Value > Fields!SalesGoal.Value, “10pt” )

Note here that we have used a different field in the second and third comparisons than is used in the first. There is no rule that says that the comparison elements need to look at the same fields.

Summary

It’s easy to see that the Expression editor in SQL Server Reporting Services can be used to build powerful and dynamic expressions that drive various formatting properties. By manipulating multiple Property Expressions for a single cell, the report designer can draw attention to various numbers and report elements if and when the numbers being reported warrant it. It is a much better viewing experience than a simple black on white report where every number is given the same emphasis.

 

 

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