Parameters are user-generated values that are not tied to a data source. These values can be used as inputs within calculated fields, reference lines, and/or filters. What makes this feature powerful is that after the author sets the limits of the values available in the parameter, the author and their users can change the value on-the-fly by using a parameter control or dashboard actions (discussed in Chapter 14).
This chapter shows you how to make a parameter, how to use dynamic parameters, and presents some popular use cases.
How to Make a Parameter
You can create a parameter by right-clicking any blank space on the Data pane or by left-clicking the down-arrow in the top-right corner of the Data pane and choosing Create Parameter.
Although parameters don’t show up in the underlying data, it helps to think of each parameter as a new column in a data source, with its single value appearing on every row. Since each parameter is a new column, you must assign it one of the six data types covered in Chapter 3. Figure 12-1 shows the Create Parameter dialog with the data type options.
Figure 12-1. Create Parameter dialog
After setting the data type of the parameter, I recommend focusing on the “Allowable values” section of the dialog, where you can limit which values can be selected. There are three radio buttons to choose from:
All (the default)
Allows the ...
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