Tutorial 4-4. Creating Multi-Value Parameters

The benefit to setting parameter options is that they give the user a more robust user interface for selecting parameter values. Let’s modify the report we created in the previous tutorial so that rather than just selecting a single Customer to print, the user can select multiple customers.

1. Open the report Basic Parameter Tutorial.rpt from Tutorial 4-3. Save it as Multi-Value Parameter Tutorial.rpt.
2. Look in the Parameter Fields list and find the Selected Country parameter. Right-click on it and select Edit.
3. For the optional properties, set the Allow Multiple Values option to True. This lets the user select the customers they want to print by either adding or creating a list of valid customers.
4. Click the OK button to save your changes. This immediately opens the Enter Values dialog box so that you can enter a new value for the parameter.
5. Refresh the report multiple times and select a different number of customers each time. They will all appear on the report.

Notice that even though we changed the parameter to be multi-value, the selection formula stayed the same. When Crystal Reports compares a single field to an array of values, you can still use the = operator to do the comparison. Crystal Reports automatically scans through the array looking for a value that matches. This is discussed more in the next section.